I don't think you have to worry about anything. I am in the process of getting ready to go to business school. I haven't even taken the GMAT yet but what I am doing is packaging my story (in my head of course). Ultimately that is what is important. People who apply to b-school come from a whole host of schools. Some Princeton, Harvard, some Santa Clara or San Jose State. Nowadays the school you go to has more to do with your financial situation at the time than your mental acuity. What I think is important is YOUR story. Where are you from? What in your personal life makes you different from anyone else who is applying. Those differences are huge, as b-schools are trying to fill there classrooms with diversity! These thinggs are extremely important, certainly more so than where you went to school or work. Furthermore it is important that you accomplish a significant amount while you are working. I am a chemist and I worked a start up company, not a big name like Pfizer or Merck. But working at a small company has it's advantages over big. More visibility, closer relationships with your boss, etc. So don't worry. You will be fine as long as you accomplish something and "package" your story well. Besides, you have a great GPA and the GMAT (especially the quant) is going to be a breeze for you!
"No! Try not. Do. Or do not. There is no try.