Not really. For some of the really intense specialties, it might hold more weight but it doesn't make your future goals impossible. All that truly matters is what you do with the opportunity that you are given. As someone who got very few As in the med school application process, I just wanted to remind you that all you need is 1 A and to make the most of it.

I'm 3.5 yrs into medical school and have interviewed for residency at some incredible institutions that I didn't even bother submitting a med school app to because I knew they would take a look at my MCAT scores and throw it out. If I could tell myself 4 years ago where I am today, I wouldn't believe it.

That being said, all you need is a single institution to take a chance on you.