Mine's a roller blader and I can so remember when I felt the same way you do.

On the positive side, it's good exercise, inexpensive, ecologically sound transportation, and skates/skateboards are much less likely to get stolen than bicycles.
We've never had any sort of serious skating injury, but I do highly recommend that you provide your son with a set of wrist guards as well as his helmet, as wrist injuries can be very common, painful, and preventable for skaters.