I think she is a little crazy because It is dangerous and I don't want her to get hurt. I have been riding and racing dirt bikes since the age of 5 (I am currently 19) and I still fall (probably hundreds of times) and I know if she gets on she will fall. I have 3 dirt-bikes (two of my racing bikes (450cc),(250cc)and the bike I had when I was 5 (50cc)). I have shown her how to ride the small bike that I used when I was 5 years old but now she wants to ride my racing bike and she can't even touch the floor ( I am 6 foot 4 and I am just big enough for my feet to reach the ground) she is 5 foot 6. I really don't want to teach her how to ride it because I am scared for her safety. My racing bikes are not toys and are very dangerous. How do I tell her I don't want her to ride them without her getting mad at me?