Feeling apprehensive about my first choice

I am a few weeks away from graduating with my BSN and have started applying to jobs. There were originally 10 hospitals on my list but most said I should apply only when I have my RN. I applied to two hospitals that didn't because about half the other students in my class have jobs already lined up and I got an offer from a very good, very well known hospital! It was a bit weird because I one day and then the following day got a call with the offer (seemed very fast to me).

The hospital has all that I want with salary, benefits, location, unit choice, and residency but I just have this odd tense feeling. It was my top pick for hospitals but it feels weird taking the first offer I get. It also feels weird because I am a loyal person and did my senior capstone clinical on a different unit than the one I applied for and feel like I may not like it as much. I loved the staff on the unit I had clinical on as well as the specialty but it was a little too fast paced for me (but maybe I could have grown into it; I don't know).

Don't know what to do. I want to accept and am highly leaning towards accepting but feel this unknown unease.