My name is Brad Cochran, and I am an Extension Agent with West Virginia State University. More than likely the reason for the excessive growth was that you may have slightly over-pruned your tree. There is a very thin line between too little pruning and too much pruning and sometimes one more cut is enough to get you over that line. Since you do have peaches starting to form it may not be such a bad idea to go through a lightly prune out some of those leaves. I would try to pull the leaves off rather than prune any more of the wood away, but this should help to ensure that your peaches grow large and also will help to mitigate any issues that may arise with disease and fungal issues due to moisture on the fruit.
Please let me know if you have other questions. You can contact me directly via email at firstname.lastname@example.org.
WVSU Extension Service