In addition to picking a major that you are interested in and that you think you will excel in, I would also try to pick a major that will allow you to pursue another career besides medicine...kind of like a back-up plan. If I had it to do over, I would probably have majored in Accounting rather than Biology. I ended up with an Accounting minor after taking my father's advice. I actually found that I enjoyed accounting just as much as I did my science classes, and the accounting major would have given me a back-up plan as well. Unless you teach or go to grad school (if you don't get in to medical school), a Biology degree really does not give you many options. I believe that environmental science would be a great degree choice if you will enjoy it.
And...you will be more apt to excel in a major if you enjoy the classes you are taking.
Just my $0.02.
The problem with me is that I'm the type of person who is interested in EVERYTHING. There are very few subjects that put me to sleep (e.g: foreign languages...ironic considering English is my third language).
Sure biology interests me. So does chemical engineering, philosophy, anthropology, physics, math, e.t.c.
I just don't want to walk into a major that will slander my GPA and prevent me from getting into medical school.
Yes, if you're interested in a subject, you'll do well, but that doesn't mean I want to have a heavy coursework or an impossible one.
One problem that prevents me from picking a B.A. over a B.S. is that I'm from a community college. I need to take biology, physics, and chemistry in order to prepare for the MCAT, which is normally done in your first two years. My first two years will be spent at a community college and I know the whole "don't take your BCPM classes at a CC, it looks bad" ordeal.
If I took EnviroSci, my excuse will at least be that the pre-reqs to transfer to my state school are the BCPM classes. Of course, there's the whole arguement whether upper-division enviroscience classes are even considered 'science' classes. That's when I need to start worrying about where I'm going to pull my LORs from :-/
Dilemma, much?