<p>Even if you are more mature than the average senior at your high school, people at a place like Caltech are going to be, in general, more mature than the average person their age. A mature 16-year-old is just not going to be the same as a mature 18-year-old. Also note that a lot of undergrads are 21 or 22. That would be a 5 or 6 year age difference, which is huge. I know I grew up a LOT between my sophomore and senior years of high school, although I like to think that I was a pretty mature 16-year-old. Those two years can make a huge difference. </p>
<p>If I were you I'd take the advice of a previous poster -- accept one of the offers and then elect to take a year off. Travel abroad, do community service, something like that. It'll give you a new depth of experience, and also an extra year that could be crucial to fitting in at college!</p>
<p>Having a good social life is SO important. And a friendship/relationship between two 19-year-olds is VERY different from that between two 16-year-olds, no matter how mature they are. Every year up until 20 or so makes a huge difference in terms of maturity. Wait that extra year, and then go off and enjoy college!</p>