when i first got into to trials i started on a 20" onza t-vee (not the best thing going lol) and it was good, i enjoyed it, it was a good starter bike. Then i quite trials. a few months ago i decided to get back into it and got a 26" bike, it feels great and in just a few short months i can do everything i could and more. I don't know if thats because of the bike or because of me but i can say i like the feel of my 26".
So my advice would be find something you like and try it, likely hood is you'll get used to it.
Hope this helps and good luck
Nick