I tried coming out at 18. It didn't go so well. I told my best friend... who then never spoke to me again. It was embarrassing, we were doing the same training scheme and would bump into each other. He completely ignored me.
I was glad when that year was over, I went off to university and never saw him again. I do wonder about him sometimes, and did a little digging. He appears to have completely vanished.
After that, in my first year at uni I had an awful experience and nailed the closet door shut until I was 26.
I had a seizure that was... misunderstood by the people I was with and my own escape was to clam up completely about it for some years.
I did eventually talk to a therapist who gave me a good explanation, it just took some time.
There were small signs all through my life, but I didn't put them together until I was in my 30s. Was in an otherwise pretty secure spot in life, so I had a very emotional but pretty ideal coming out experience. Both friends and work were accepting, and my family was already no contact