Now is a good time for a prune. You don't have to be gentle. If you want to do drastic pruning this is a good time of year for it. But it is okay to take off less. These are young trees, prune now, then let grow out.
Basically, for most of my deciduous trees, I let them grow until early to middle of summer. Then if they are going to get a hard prune, that would happen between beginning of June thru the middle of July. Then I would leave them more or less alone until the following spring. Repot if needed then a pruning right about now.
Basically, repot early spring. One pruning early summer. Wire and touch up pruning late summer. Repeat. beginning with the early spring repot.
It can be made a much more complicated schedule, but basically, this is the cycle.
