How do we get our parents to support our dreams/future plans for Hollywood?

If you really want to be an actress you need to go out on your own. That means finishing school and getting some kind of training so that you can support yourself and take acting lessons and go for auditions. You won't be able to do that until you have graduated from high school, so shelve your plans until then. It isn't fair to ask your parents to put their lives and their marriage and maybe siblings if you have them, all on hold for you.