She needs a LOT of conditioning/muscle development (in the right places) before you do anything serious with her! IMO But she is cute :)
She looks a bit over the knee and a little pigeon toed in the back but some horses just stand funny, like my mare, and end up being good jumpers regardless. However, I don't do a lot of jumping and overtime the stress could cause some damage to your horse.
I don't know your experience level, but just start her slow, PLEASE do not rush things!
Judging from the horse's neck/head set, doing a lot of trot work, encourgaing him/her to stretch_ long_and_low, over ground poles would work wonders on their top-line AND gain muscle on the top of the neck instead of underneath it!