You're definitely going to need better pictures for a critique, you can hardly tell anything from dark and blurry pictures and definitely not enough to be accurate... Preferably having her stand squared up. Pictures should be one of each side, one of the font, and one of the back.. On flat ground..
How old is she? She's has a rather long back or a weak back, a bit butt high.. Is she just standing funny? Her back legs look a little wonky to me.. Her should is a little upright..She may have back problems along the way when barrel racing. I think she'd be okay at a local level but she doesn't have the conformation for higher levels. What are you planning on doing with her barrel wise?
I don't think she'd be bad at it as long as you watch her back and for any physical problems that may come up. Remember to absolutely take barrel work SLLLLLLOW..Are you going to be working with a trainer?