I am actually sort of jealous of you for that. You are going to have so much fun, especially if your small group sticks together.
That being said, play what you want, what you enjoy. Having done just what you are going to do, part of the fun is making it work. You can’t go wrong with either choice of tank anyway.
If, down the road for whatever reason you want to raid, level up a warrior if you don’t already have one.