I am having difficulty with my horse. She turns before I get to the barrel. She is a push style horse and I do not know if it is a problem with my body positioning sitting down to soon or if there are drills that we can do that may be beneficial. Any aid would be greatly appreceiated. 

As a person who went through this back before I knew more.... please start with a very thorough vet exam to rule that out.  Horses don't just suddenly start doing something like that.  It's either a pain thing first and foremost or it's them thinking that they are doing what you are asking.  If you have ruled out pain and bleeding, then really examine yourself and your body position in runs.  If our mind isn't right, our body will do things in a run that we don't THINK we are.  I think after a vet exam, the best thing you can do is go ride with an experienced barrel trainer that can help you in person.

My mare does this and it is entirely my fault, EVERY time.  Watching the slow motion videos shows me getting ready for the turn way too early, and she is responding to my cues.  It only happens in a real run, of course!  That may not be your issue, but that is my current experience.

The last horse that randomly did it had an issue with his neck, that we finally discovered by xray with the 4th vet, so there's always that possiblility.

Good luck. 

When you say turns before the barrel do you mean she is ducking, or just turning too early and hitting barrels? 

First make sure you've ruled out any pain issues.

I had a push style mare, for a few years I could not make 2 clean runs in a row, we'd drag barrels over. After watching a few videos in slow motion we figured out I was still kicking but I'd slightly roll down in my saddle telling her to turn. After I started focusing on keeping myself in the "go" position we quit dragging down so many barrels, I would also pick a spot on the fence and focus there until I got to my point to turn. Good Luck

If you can video yourself during a barrel run . Possibly slow it down to see if your asking to soon. May have to retrain yourself to sit at the barrel and not before and don't use your rein for the turn until a stride past the barrel.

I had a mare do this. She was trained to go to the right barrel. I switched her to the left & she quit ducking. And I took her to my vet & she needed stifle injections. After the injections & changing her to the left, she never ducked again.