This is a great question. I was older then all of my friends when I started having sex but I just wanted to wait for the "right one". Needless to say, I honestly don't think it works that way. I'd say wait as long as you want to and if you don't want to wait make sure you are prepared. Always ALWAYS use protection because you never know.
As far as changing your personality/ character, I'd have to say that it can be a confidence boost, and it certainly does things for your mood.