I am a 13 year old Writer, or trying to be please help!!!?

Hey, well i don't know if I am old enough to write a boook, but i'm writing a book right nw called 7 destinationa. It's about a girl who can talk to animals and see mystical creatures in the forest once she turns 13. Including sea serpents, dragons trolls, ogres, Giants, unicorns, half man half horse, and so on. The fascilians, or the so called bad guys, are the race of the dragons. They are trying to steal the ruby that protects the forbidden city to destroy their kingdom. They have to collect a gem from each of the seven destinations that has a special power, and protects their kingdom. They have to get to the city and get all the gems before the dragons do. They try to kill the girl and so on, and she makes animal friends along the way, what do you think? The leader of the dragons is Firebreather, and he is trying to turn the whole kingdom into evil, and he has trolls ogres, dragons, and all sorts of creatures that work for him.