I agree with SorrelHorse.
She needs to be trained for barrels, before you can expect her to run them, so of course she "can't run barrels for the life of her". She's not trained!!! And the fact that you say she has an attitude implies to me that you can't always control her and/or get her to do what you ask, and she (or you) may need training in general.
It takes a lot to train a horse for barrels which is why entire books have been written and entire DVD training sets have been created. And it takes time. Expect anywhere from 8 months to 2 years to have a fully trained and seasoned barrel horse.
I would definitely get yourself a barrel racing trainer to help you hands on. We can rattle off tips and advice here on the internet, but if you've never done it and if you have trouble with your own horse (because she has "an attitude") you will not be as successfull as if you being trained in person.
∞•*˚ Βгįťţαňγ ˚*•∞
It is not enough to know how to ride; one must know how to fall.