Diseased peach tree
Tree is young and has developed a leaf lumpiness on most leaves (see photo).
Certified GKH Gardening Expert
This is Peach Curl disease that can be treated with a fungicide.
Here are a few links with more information.
I'm afraid that this a classic case of peach leaf curl, a very common virus disease. You can control by spraying with a fungicide in Jan/Feb and again now.
Pick off all diseased leaves.
Moving the peach indoors under glass can also work.