I was about to reply by asking if there was anyone that developed SA later in life. My understanding was that it typically developed early on, was sometimes not noticeable until early teens, or later teens...and then I read Kiwong's post.
I have always been shy and introverted. Although very talkative when I was very young, I remember having frequent stomach aches when I was 9 or 10 that were probably related to anxiety and stress. Only when I look back now do I think that those may have been the earliest symptoms of what became SA later in life. Until I was 18 years old, when I went to college and my SA came on full force, my father's job took the family all over the world. Being the new kid and often the only American in my school, I had people approach me and want to be friends out of curiosity. I never had to learn how to make friends, not that ever I had that many.
I don't know if it would be easier to have developed SA much later. I'm pretty sure it's difficult no matter when it develops, because it shapes your whole world from that point on.