Do you think I'm a good writer. I'm 15, going into sopre year?

It's decent. I think you fell into the trap that many young writers seem to battle with: You use huge words excessively, and unnecessarily. I used to be that way too, but a semester of creative writing changed my habits. Just keep in mind that you don't need to prove anything to the reader, which is what wordiness comes off as. The plot needs to speak for itself, as does the emotional value of whatever you are writing, so just write without the thesaurus (unless absolutely necessary, of course).