How do I become a good cheerleader?

Well, I love cheering and I really wanna try out for my 8th grade team there's just some slight problems I haven't taken any cheer or tumble classes.. I can barely do a cartwheel and barley a handstand.. and that's all I can do I can't do any other tumbling things like the splits or etc. My friends say I should try out but, I'm afraid I'm going to embarrass myself in front of everybody else trying out! I just want to know how I can start working on my tumbling skills that way I can be a better tumbler and cheerleader! (: Any good and helpful answers will help me alot! (: