I have started, quite deliberately, referring to our garbage cans as “the bins,” and to the garbage collectors who come around every week as “the bin men.” My wife just shakes her head.
“He” as in Matt Groening? He’s older than me, almost like 70, I think.
I have also tried to get rid of you know and have replaced it with “of course.” That’s probably no better.
So, my experience is different 
I’m GenX, and use “so” at the beginning of some sentences. My GenX brothers, and most of my GenX friends do the same.
Yeah, same. My cohort is all on the younger side of GenX, but we’re nevertheless in the range, and use So… all the time. Maybe even more often than younger crowds.
Thanks to some Youtubers I follow, I’ve adopted the adjective “boujie” (meaning “upscale” or “pricey”). I’m not sure of the spelling – it’s pronounced “BOO-zhee.” YMMV.
I always assumed this had something to do with the {insert your Liberal Arts elective} word “Bourgeois”, although I guess it wouldn’t make sense based on its definition being “middle class”.
ETA: Apparently urbandictionary made the same connection: Urban Dictionary: boujie
Out of curiosity: Have you done it for decades, or mostly over the last 10-15 years? Did you use the “So …” lead in, say, as high-schoolers?
EDIT: “So …” could also be a regionalism that spread out later.
I’m sure there’s some bleed-through between broad cohorts. Some people are a young 40 or 50, and other people of those ages kind of have “ossified” minds (I’m one of the ossified folks).
I’m now curious if there’s a correlation between older folks adopting younger folks’ speech habits, and things like “adoption of up-to-date fashion/hairstyles” and “appreciation of right-now popular music”. Probably some fairly complicated and multifactorial dynamic at work.
(Circa 1969 … were there people who unequivocally presented as “hippies”, and yet were already middle-aged? I’m sure there were.)
For me – I’m 46 – it feels like something I’ve always used, but it’s really hard to say, because if it did start 10-15 years ago, that long enough for it to feel like I’ve always been doing it. The vast majority of people in my social circle are Gen Xers, and I’ve never been around large groups of Millennials or Zoomers regularly to adopt their habits, so if I got it from anywhere else, it would have been media.
Well, I just remembered I have some letter transcriptions saved on my hard drive. I have one from October 24, 1998, with the first paragraph: “So, what’s the future got in store for Ms. XXXX?” Second paragraph starts: “So here I am in a little cabin just outside Bakonybel in Western Hungary.” A few sentences later: “So I was invited by Eszter, this girl from my German class …” I think those all qualify as examples suiting the usage of “so” you’re looking for, right?
It’s more of a spoken-word thing than something that comes across in print IMHO.
It’s not simply the use of “So …” to open a sentence. There a fall in pitch and kind of a drag/lull/pause in the utterance after the “So …”.
I’ll make a comparison to another spoken-word trend that was prominent at the turn of the millenium: The sarcastic “Could [someone] BE any more [adjective]?” construction, with heavy emphasis on “BE” and a hint of a pause after the “BE”. Example: “Could you BE any more dense?” My recall is that this got widely popularized from the sitcom Friends, though I’m sure many Dopers can and will attest to having heard/used the construction before the show debuted in 1994 (after all, the writers got it from somewhere). And I’m sure there are legion examples of similar constructions in English-language literature, film, broadcast media, etc. going back centuries. But it wasn’t a commonly-heard thing coast to coast until Friends got popular – at least to my memory.
Anyway, the lilting spoken word “So …” is kind of like that.
Sure, but my letter was written in a colloquial, speaking-voice style, so it reflected my speech patterns. The first sentence definitely would have been spoken as “Soooo,” with a fall and a pause in my head. (The first actually notates the pause with a comma.) The middle and last one might have been spoken straight through or they may have had a similar pause and fall intended in them. I know I must have other letters around where I notated the type of “so” I think you’re looking for as “So…” like “So…what’s new with you?”
Expressions like the bolded are familiar and don’t come off as trendy new-speak. Here’s a nonce conversation that gets more to what I thought the OP was going for.
A: “Hey, thanks for coming over to feed my cat when I was out of town. Did she give you any trouble?”
B: “So … once when I came over, she was hiding under the bed and wouldn’t come get her food. But when I came back the next day to feed her again, the food was gone so I guess she ate it.”
A. “Yeah, she’ll be shy like that sometimes. Hey – you want to go to lunch in a little bit?”
B: “So … I have to finish up this TPS report for my boss. But I can meet up right after that.”
A. “Cool. You think by 12:30?”
B. “So … it’s kind of a complicated report, but if I try and hurry up, I should be done by then.”
…
Now that I’ve written this up, it looks like the new-speak “So …” thing is most commonly found in response to direct questions. Perhaps the declarative “So …” (like in your written-word examples above) is a different thing.
Where’s a good sociolinguist when you need one? 
All those sound perfectly normal to me; however, I don’t have any sound recordings from myself from the 90s to confirm, but it doesn’t feel to me like something new I picked up. I could be wrong – like I said, I’ve been using it for so long that it’s hard to tell when it started.
Yeah, I don’t think I’ve ever heard “simp” used in a context that wasn’t completely misogynistic. It pretty much says, “What kind of a man would actually care what some woman thinks?!?”
Historically, we’d have probably called the guy a “fag” in the same context, so maybe look at it in that light, and do what you can to get him to cut that shit out.
Did we read the same crappy article about Gwyneth Paltrow just to find out what “slappin” meant?
I’ll go along with pulykamell , and say I use “so” at the beginning of a sentence fairly often. Both written and spoken. I think we are similar ages and I also couldn’t say how long I’ve been doing it. It just seems like I always have.
I’m 50, and have spent most of my life in metro Atlanta, but I can’t answer your question with accuracy.
So what?
I had problems spelling “Wednesday” until third-grade, 9-years old, until I started saying “Wed-nes-day” (silently) to myself when ever I spelled it. Still do that.
Me too. I do that will all sorts of troublesome words.
Like many here I got sick of hearing “like” and “you know” tossed into speech but couldn’t stop myself from doing it. I agree, placeholder words are useful and important, so I have been trying to train myself to say “ass” instead. Ass is a fun word, no longer banned in most media, handy for building constructions such as “hard-ass”, “crazy-ass”, “wise-ass” and many more to come.
Really, ass, you can ass intensify any adjective by ass adding “ass” to it; it’s just ass so obvious as well as ass thoughtful-ass for all those who are ass tired of hearing “ass” and “ass” get abused.