You did a good job on this chopper. You seem to be rather young, and your sister even younger. I think you´re starting out just fine; all builders here started out like this at a certain point. Concerning the ones who write mean things here, don´t listen to them. It seems they don´t care about age at all, which is an important factor. You are creative, you are making town layouts and aircrafts - just keep on building and always trying new things and new ways to construct.
So you´re Australian? Did you ever see a road train? Check out mine if you would like:)