I am 23 and just got MY first snake. My dad had a BP when I was younger and I've wanted one for myself ever since. I own 2 dogs too, a rescued pitbull and a Pomeranian mix I bought for my fiancee.
As far as the "grow up" comment, well I think that's just ridiculous. As a new snake owner I just learned all the responsibility that comes along with owning a snake. Anything that can teach responsibility is good for people of any age.
Plus snakes are just cool creatures. They're so much better than a bird or whatever else "grown people" own.