Should i do cheer? Help please?

I want to do cheer in highschool so bad. My mom told me i could try out but she says she knows for a fact that i won't make it, Because all the other girls trying out have probably done cheer their whole life and probably have a lot of experience. THe only time i did cheer was in third grade for some church thing, but i really want to do this. I want to be mascot because im really outgoing and funny. What are some things you have to do to become mascot or cheerleader? Should i try out? Do i have a chance of making it? Try outs are next week help please and just to let you know i will be in ninth grade next year