Starting bmx ??????...?

ive had my bmx for ages now its a mongoose mischeif not customized or anythin its 31lbs. im 16 in the summer but would like to learn how to do stunts, i can just about do a bunny hop but its very heavy lol ive been watching vids on utube and trying them for ages but just wont work theres no skate parks near me so i cant realy teach myself what else can i do