I'm not a fruit tree expert, but I prune to ensure air flow, easy access, and no branch rubbing. I've found that branches which don't get much direct sun still grow fine (if a bit slower) and the fruit that set sometimes are better hidden from tree rats and birds (more a wish). The rubbing is the biggest item for me, when the limbs get weighted with fruit, especially when leaves and limbs are wet in a windy storm, branch rubbing causes problems. Since this is your second year, you probably can't really see the full growth pattern. I generally let the tree fill out a few more years before doing any major pruning.