As someone who has coached kids and worked with them at school, I try to keep in mind that she is still growing and learning. Her mind is still developing and her body is still maturing. She will no doubt only get better as time goes by and this applies not only to motorcycling but everything she puts her mind and heart too. She's only 15 so I'm thinking that motorcycling is only one small aspect of her high school life right now.
Whenever I hear that a person is "too small" or "too slow", or anything like that I think back to the story of a man whose looked more like a grocery store clerk than a football player. He had poor eye sight, was born with one leg longer than the other and did not have blazing speed at a position that requires it. All his life he had been told that he just did not have what it took to be a football player. His first two years in the league were spent living in dread of getting cut. Yet on the day he retired he held EVERY record (since then broken) that a wide reciever could have. Imagine how poorer the world of the NFL would have been if Raymond Berry had listened to the nay sayers and never played. Unitas to Berry, no one could argue the success of those two.