From what I can see, you should be fine.
Believe it or not, I managed to smash out a massive ZERO
pull-ups on my selection, I couldn't even manage one.
I still got in, got through basic, and am now a PTI, so don't
worry too much about it. Do your best, but don't stress.
Adrenaline will help slightly, as well as the fact that you're
doing them in front of your peers.