I feel that the majority of 2 yr old horses will always be butt high. My 2 yr old gelding is DEF butt high, lol. I think she is gorgeous and for being 2 she has some nice hind quarters. Also alot of young QH will be sickle hocked or where their hind toes will point outwards because as they grow and their rear fills out it will bring the toes in and the hocks straight. Very difficult to explain but owning QH my whole life, all they young ones have always been like this confirmation wise till they were 3-5 yrs of age and they have filled out!! So I definitely wouldn't be worried about any of that.
All in all I think she looks like your typical young misproportioned QH. I would like to see her at age 4-5, she will be STUNNING!! Beautiful filly you have there.