I like how you call him your bf already. I think you will do well no matter what course of action you take. He is considerate, he wants to take things slowly - what more can you wish more? It is possible that you were sore from fingering in the past because you were not really wet/excited. That means that this time around you might well be ready for fingering, since you do want to have sex with the guy. Your past experience is not necessarily a good predictor of future experiences, in my view.