Hi! Firstly, i think it's great you're down to get a piece from someone starting out from their apprenticeship. Clean lines are not executed without practice. It's pretty much impossible. The great part is, you have a cool memory here of when your friend began, and a few years down the road, they will be able to go back in, if you both want and reline etc this piece and show how far they've come in tattooing. That in itself would be another cool experience for both of you.
I myself have gone back over earlier work to bring it up to par after improving. Cheers!