I say go for it. You sound like you’ve got the qualifications they’re looking for.
On the other hand, I might recommend other schools, but not because I think your chances are poor. When I was in high school, physics was my one true love: I ate, drank, and slept physics (sort of, I was also into photography (what I considered the most ‘scientific’ of the arts) and sports. But physics was still my #1 interest). My dream was to go to MIT, but I was also looking at Harvey Mudd, Northwestern and RPI. My parents, and a few other people, got me thinking about Harvard, on the grounds that a) it had just as good a science program as MIT (I was unconvinced) and b) it would be good for me to be around people who had academic interests other than physics. I got accepted at both, and eventually decided on Harvard because it seemed like a fun, friendly place, and they had a credit exchange program where I could take classes at MIT for credit if I wanted.
In my second year, I went through some major changes, one of the results of which was that I switched my major from physics to European history. Since I was going to a school that had strong programs in both, this wasn’t a huge problem. Had I chosen a school where the focus was more exclusively on science, I may have found myself in more of a bind. As an added bonus, my parents were right about hanging around people with different interests.
Anyway, I guess my point is that I really like talking about myself. No, wait… my point is that although you may be really into biology now, you may find something down the line that really catches your heart and mind that’s in a completely different field. You should keep this possibility in mind when you choose a school, and maybe look at place with strong programs in a wide variety of fields.
Good luck whichever school you choose.
Oh, and by the way, the most valuable things I got from college were the social education, the broadening of my horizons, and a general interest in continuing to learn about the world. My actual classes (both physics and history) ended up having almost nothing to do with what I’m using now.