My fifteen year old self often - okay, ALWAYS - asked if "this is the real thing" but that didn't mean I would hop into bed with the person if it was, it meant I might be more open to meeting, dating, getting more emotionally involved...

I think that as we age, we tend to still consider ourselves as the median or the norm, which might explain why, as people age, they refer to an increasing bracket of others as "kids."

There's also this current, it seems, in most of America and English Canada that early sex necessarily implies an emotional or physical crisis, and while it may be true in some cases (pregnancy, rape, etc) I would argue that for most it's not the dangerous activity that adults imagine.