Yep–me, too. And for a very long time after I was exposed to analog clock teaching, I had to say (under my breath) 15, 20, 25, 30, 35. It’s 11:35! etc.
I don’t remember at all when I learned it. I do remember when my son did. He must have been 5. I had tried numerous times to teach him, and he just didn’t get it.
Then we went shoe shopping one day, and he focused on a pair of shoes he REALLY wanted. They were lace-ups, not Velcro. I told him I wouldn’t buy them unless he knew how to tie shoelaces. He learned on the spot in about two tries.