Skateboarding: will someone help my ollie?

im a 15 yr old girl learning to skateboard against the guys. my guy friends say that girls cannot skateboard. so im working on proving them wrong. i need help however, my ollie is sad. if i even get off the ground, its very low. i dont really know how to pop it up right anyways. i also am not sure where the weight of your body is supposed to be when you are sliding your foot, kicking it up, and landing. also, do shoes have alot to do with skateboarding or can i just skate in my normal shoes? do i have to get like adios or vans or etnies or something? <3thnx for the help : )