It was not good circumstances I moved out under. I was 18 and my sister was 17 she spent her entire life trying to get me in trouble and beat up by my father. One day she literally smiled at me and then through herself across the kitchen knocking over tables and chairs. I knew I was going to get beat on so I said what the hell and punched her right between the shoulder blades then ran out of the house and never came back.
Hard to say. When I went off to college, I lived at home, about 2 miles from campus. A year and a half later, they moved to the 'burbs, which made the commute harder. A year and a half after that I got an apartment near campus with a friend. My mother blew her stack: “A person lives at home until they get married. My cousin Ruth will think we couldn’t get along. Blah blah.” But every Friday evening I packed up a suitcase with a week’s worth of dirty clothes and ventured out to the 'burbs and came back Monday morning with a suitcase of clean clothes. We kept this up for two years. The second of those years, I was effectively (though not actually) a grad student and a TA. After that I spent some time sharing an apartment with someone else and living at home. The last year I stayed home and my mother typed my thesis. Then I got a job in NY and never lived home again.
In my 2nd year of college I got a full time job so I bought a mobile home and moved out. Paid it off and bought a house. I went from full time school to part time. Took forever to finish.
Went to college within an hour’s drive of my parent’s house, but living in the dorms and not having a car meant I really only saw them on breaks. Got a job in DC starting the week after graduation and rented a room sight unseen in the dingiest flophouse you can imagine. My Dad drove me up and – after seeing my new accommodations – offered to drive me right back if I wanted. But I stuck it out.
I was 19, hating college after looking forward to it for so long. On a whim, I went to talk to a Navy recruiter and 3 months later when there was an available billet, I headed off to boot camp. That was that. It was still a few years before I got all my stuff out of my parents’ house, but I never lived with them again.
Graduated college at 20, found a stable government job. Crazy home life, moved out the week after my father’s wife came after me with a knife (she was mentally ill, and quite violent for many years).
So… I guess about 20 1/2. Best, safest decision of my life.
I know you ruled out college, OP, but the fact is, while in college, I moved in with my boyfriend and married him two weeks after graduation. I was 19 when we met, 20 when we married. My mother had been very upset when I moved in with him, but marriage fixed that. Six weeks after the wedding, we moved from Illinois to New England and then to the Rocky Mountain West. I thought I was mature, but I had to grow up fast after the wedding.
I tried to phrase my OP broadly so as not to rule out anything. You formed a new household while you were in college - that’s exactly what I’m looking for.
These are great stories, y’all. Thanks.
After graduating high school, I was living with my grandmother and great grandmother. I was reluctantly going to the local junior college, and even more reluctantly to church.
At this time, my boyfriend moved out of his family’s home, and invited me to join him. Actually, it was more of an ultimatum. I could be his live-in girlfriend, or no girlfriend at all. The rest is really stupid history.
My parents divorced when I was about three years old, and my father quickly vanished from my life. As a result, I grew up the son of a single mother. At the end of my junior year in high school, my mom had a sudden, fatal heart attack. I had to move from Houston to Austin to live with my aunt and uncle, but as their oldest kid was 8 at the time, it wasn’t a smooth adjustment for any of us. I ended up moving out six months later into a crappy one-room apartment near campus.
Went off to college 2 weeks before I turned 18. Hated the dorms: nice people, but I did not do well sharing a room. Got an apartment with a friend 3 months later, and just never went “home” for more than a visit.
Growing up, my parents used to say that they’d “break my [dinner] plate” when I was 16, i.e. kick me out of the house. They were joking, but they made that joke a lot. That, and stressing how they were raising me to be ready to live on my own, meant I really was ready to move out when I was about 17. Not that I was terribly mature or anything! I didn’t know how to cook or clean or budget, and I certainly wasn’t socially mature. But you get there in the end, don’t you?
Sigh. Yeah, somehow you do…
I had a job, I rented a house with some friends, I packed up a few things, said goodbye and I just left. Parents didn’t say a thing.
A year or so previously, I wanted to do the same thing, but I asked them first and they said “No.” I guess they figured if I still felt like I needed to ask their permission, I wasn’t ready. They were probably right.
I grew up in a very unhappy home, but I stayed there way too long because I was lazy and didn’t make much money. I lived in the furnished basement of my parents’ house, it had a tiny kitchenette, a water closet, and I had a nice big room I tried to make more into a sitting room type of space. I was in my early 20’s and believe you me, it was very awkward when my boyfriend came to visit. (Of course we sat in my room, where else were we going to visit?). My parents despised me but their main attention was taken up by a mentally ill brother who also lived in their house. Eventually, when I was about 23 or 24 my boss said her sister lived in a little old house with her husband and kids, and the flat upstairs was being fixed up and painted so as to be available for rental. They scoped me out and decided I was OK, so I moved into that tiny decrepit little flat and lived there for a few years, paid rent (in the late 70’s) of the grand sum of $135 a month! I was working and had benefits, a car, so I made out pretty well. ( I stayed there till another boyfriend and I bought a house in the suburbs. He moved out there and I joined him some months later, then we got married by a justice of the peace. I told him my name was on the house title and I wasn’t going to be a ‘live-in’.)
Graduated HS in 2003 and went straight to college 3 hours away. Flunked out in Winter of 2004 and moved back in. I picked up a job at Burger King but despite working full-time I didn’t make enough to afford rent for a place on my own (admittedly, I didn’t search very hard).
In October 2006 (21 years old) I got a new job and half a year later moved in with a friend. I lived with roommates until 2011 when I had to move back in with my dad because of difficulties with both our living situations. I moved back out (this time on my own) in 2012 and have lived alone ever since.
6 years at pharmacy school in Philadelphia: close enough to come home every weekend and holidays (hey, somebody had to do my laundry).
4 years at medical school in Cleveland: came home every Xmas and summer break.
Residency in Miami: came home every X-mas break.
Moved to NE Florida and lived in an apartment for 2 years: didn’t come home.
Bought house in NE Florida: parents moved in with me for a few years until I got married.
Got married and moved across town with wife (then 2 kids): parents bought house next door and lived there until they died.
Got divorced: me and the kids moved next door into parents’ vacated house.
Oldest kid moved to Kansas (art school): youngest kid stayed with me.
Youngest kid’s boyfriend and his 4 cats moved in with me, daughter, and 1 cat.
Just when I thought I was out, they pulled me back in! 
I’ll add that when I moved out in the mid 80’s at 23 yo it was to a house my boyfriend and I rented near the beach. My folks were cool with us cohabitating, they liked him. I eventually married him. His parents staunch CRC acolytes otoh were not cool. I met them previously and all was well. Until we were warned by his brother that his parents were coming down to visit us and to scope out our situation. Omg the drama first my man the chicken shit wanted to remove all evidence that I lived there, I refused. So we met his P’s at a restaurant and told them we’re living together. I remember it was me who broke the silence and said we’re roommates. They expected an engagement. The shit hit the fan! I’m like da fuck! His Mom is crying, dad is cursing and calling me names. They were so concerned about what other people from their church would think about them.
They left and stopped all contact with their son for a good year. Good Lord it was a blessing.
I was a high school dropout with a GED living at home when I met my now-wife when I was 19. We fell in love and decided that we just had to be together all the time and all that horseshit so decided to move in together. She was two years older that I was and had lived wither sister in Texas and Virginia before coming back to Oregon and moving back in with her parents. We rented a shitty little 2-bedroom apartment in a 4-plex in the bad part of town but it was ours and we loved it. We could get pizza delivery, not worry about making too much noiseand pissing off the parents, and watch all the movies and TV shows we wanted to watch (her parents were fundie Christians and anything PG-13 and above was forbidden in their house – even for their adult daughter 
). Life was good and I felt free. We ended up getting married, having kids, and going to college in that order.
We went to separate colleges so I lived ~3 hours away from her and the kids while finishing my BA. Other than those 19 months we’ve been together since the day I moved out of my parent’s house.
I could go on a very long screed about whether this was the right choice and whether or not I’m still happy with it (or the long-term impacts of it). But it was the choice I made and it is what it is.
At age 22, I had been living at home, working part time, and going to school for many, many years and I felt something needed to change. I was needing to spend more and more time in the campus libraries and the driving back and forth twice a day was wearing. I determined that if I lived near campus, there would only be a single back and forth trip to work so I looked at a room in a rooming house and moved out. It turned out that I made the announcement the same day my younger brother announced that he was moving closer to his job.
Two years later, I moved back home. I was flat broke due to a car accident and the need to take a lower-paying job as my internship. As my education was self-funded, my parents were thrilled that one of their 4 kids was about to get a BA and allowed me to move back home. Their decision was also self motivated. They wanted me to pay their bills, visit grandma in the nursing home, and keep things ticking over at home while they took a retirement trip visiting friends. Deal made I moved home, got my final class in and graduated. My parents asked me to stay on another year as I found my first full-time job and they continued their vacation and went house-hunting. That worked for me so I did.
Then one day they called with the exciting but dreadful news that they had found a home and it was time for me to move out. It was dreadful because I had just lost my job due to a recession on the very same day. My mother said, “Too bad, but you must move.” So I did. Reality bites, indeed.
18 after I came back visiting my relatives in Belgium after HS graduation, My Mom said get a job and move out. I found a place with two other girls for 80 bucks a week, heat included.