My little brother is 15, 6' tall, 120 lbs. I try to get him more enthusiastic, maybe interested in racing. His first ride was over 20 miles at around 17/18 mph. He could be a killer climber

Scrod, how do I get a 15 year old really interested in more than just slow party rides? I don't want to force him and give him a bad taste because I pushed him a little too hard.