Anyone can apply and go to college, not everyone given a real opportunity to shine.
My only regret is the major I picked. If I had it to do all over again, I would have done Computer Science, and learned how to program.
Along the way, I had many opportunities like the one you're being presented with, to work in SF for that company. I took them. It has led to a successful career. I'm currently in Europe for my employer... third such trip.
Personally, I think you are making a HUGE mistake in not taking the offer from the company. MASSIVE.
A quote attributed to Mark Twain... "Don't let schooling interfere with your education." and I think he was SPOT ON.
Your greatest education isn't going to come from the halls of a school/university. It will come from getting your hands dirty (so to speak) in your vocation.
And with the right experience, which I'm guessing you'd get at this firm... a degree matters even less and less.
I think you should reconsider. Seriously.
In any case, it's your decision, and I wish you well. If you have any questions, and want to talk more... feel free to drop me a line. My user at G mail.