I can speak from experience here-
I started running track when I was 7 years old. By age 10, I was competing at the state level in the 1500m run. There were times that I'd go out & run with my dad, and other runners would look conerned because I'd be red-faced and looking like I was about to pass out. If you'd asked me if I was having fun, I would have told you NO, but if you asked if I wanted to quit, I would have also said NO. If I DID want to quit, my dad would always encourage me to keep pushing, and I usually did. He never forced me to do anything, but he didn't want me to give up early, either. A lot of it had to do with my stubborn and infinately competitive personality. Some kids are stubborn like that.

This very well may have not been the case in your situation, but I figured maybe I could put in a different perspective.