I can only speak from personal experience. I learned to ride a bike late as a kid. I was 10 and decided that it was way past time to learn, so I used my cousin's 20" girls bike for practice. Her parent's driveway had a gentle slope, so I used that as a launch point. About 30 minutes later I was pedaling and had the balance skills. I didn't have a bike until I was twelve, and that was my older sister's 26" bike that I had to fix up.