Its up to you but I wouldnt shave anything yet. Try 2 pieces to fill in the receeding bits see how it looks.

This way you'll have your own hair at the front. You could also brush your forelock a little to the left and right mixing the pieces with your own hair should give a flawless look.

I wear a really small piece (although I was advised to shave it) and I grow my hair long and mix the piece in with existing hair and it looks great.