This seems very true when you consider traumatized, sexually-abused children. Then again, what about the 40-year-old-virgins???
Sex with what?
touché
I think it depends upon the person and their cumulative life experiences up to that time.
You don’t think it matters what they were having sex with?
I am flattered by your post, RU - I observe people more than actually experiencing life myself, and noticed this through observing friends and family…
Those who have sex young seem very childish and immature / those who have sex later in life (especially post-teens) are more aware of things as they have observed more, but they seem to tend to annoy others more than their younger counterparts…
Yes Kris, I see it as the cumulative experiences of the virgin up until the point that they are no longer a virgin - my sister is stuck at 13 (yes, 13) and we just don’t get on, as she annoys the hell out of me with her bitchy whineyness which she cannot seem to progress from…
I don’t know if it makes a difference with who/what you have sex with, Smears! 
although I have thought about this, and think it has to involve some sort of emotional connection that we only seem to get from another human… I could be wrong!
I don’t think all virgins get stuck, besides experience, I think personality has much to do with it and if a baby/pregnancy becomes involved. My dear niece become a mother at 14, again at 17 She is now a RN. She lived with us shortly at the age 13 she was a strong young lady very set and determined. A single parent and a very successful one to have started at such a tender age. She is probably the exception. But personality does have something to do with how you aproach life after devirgining. your sister’s personality directs her attitude as much as the experiences, especially the whiny bitchiness. if she had held off she would probably would have been insufferable as a mate, even worse than she is.
Not so much stuck, but a defining moment in one’s life would sum up what I am trying to convey better…