Was thinking about this the other day.
A couple of people I’ve known that were sexually active younger than average also looked quite a bit older (as you get older this is a bad thing but in youth this is a bonus.) They might have also peaked younger and end up as unattractive adults but dating experience and attention from the opposite sex gave them some confidence in their interactions going forward.
A lot of times I’ve met an unattractive person who seemed really confident talking to them they turned out to be an early bloomer.
Personally I was a late bloomer. At 17 I looked like a giant 12 year old even though I exercised regularly. I looked OK/average in my 20s but had zero self confidence.