Hi Alex I started on a normal mountain bike when i was 13 it does take some effort but you will get there its just practice, practice, practice. I got a 20" trials bike about 5 years later i still ride a 20" now but also still ride 26" too just not as often. I would recommend getting a 20" now most get on with them and get very good within a year. Also most 26" now are a lot lighter than they use't to be so that is an option too, see if anyone you know will let you have ago on theirs and see what you think.