How does she know she is suppose to stand still for you to mount?
Have you done any ground work with her before you get on? Is she there with you mentally?
Horses are fight or flight animals, they prefer to flee however. They are preyed upon, they need to feel they can trust you and you are their partner, a team, working together. You climbing on her back, how does she know she can trust you? How does she know she is suppose to stand still for you to get on her?
Its best to look at this from the horses point of view. Its never ever the horses fault. If there is a problem we need to look upon ourselves and our training, or lack of, and know what we are trying to teach the horse before we ask the horse to do it.
My suggestion is to do groundwork first. Sending, yield the hindquarters, changing eyes, follow a feel, lateral flexion, disengage the hindquarters, climb up on the fence and sit up there, is she ok with ALL of those things? If not she isnt ready for you to mount. If she is, she will happily stand for you to mount.
She does good with all that stuff, she usually does really good with ground work and she listens really well and she dosn't gwt scared of me when I walk behind her and she's fine when I'm actually ON her she just moves when I get on. I am pretty new to this since my parents wouldn't let me ride til i was 12 so I've oly been riding for about a year.
I am in TOTAL agreement with the others about teaching your horse to stand still while you mount. We are doing just that with our 3 yr old gelding. For us, it is VITAL that he learns this, because in the future he'll be at some of the largest National CW events (as our hobby winds down.) Things get very hairy and your horse can get very upset by all of the action. Here is our training, which, BTW, we only do only on weekends this time of year. I do NOT have an indoor arena in my back yard, but if my ship ever comes in, I will. :
We lead "Sweet Cup'n'Cakes" into our small arena (55 ft x 65 ft)
We walk him over to our mounting block, and the person NOT riding holds him there.
IF he turns outward on the forehand, we push him back into position (had to do this 4 x yesterday)
Rider plays with the saddle, like hanging on it to see if it's tight
Rider mounts
We count a full 5 minutes before he is asked to move out.
IF he steps forward, we halt, and start the clock again.
I was SO pleased with him yesterday, because my DD was riding our mare, and she left the gate to our small arena open. I worked on both Left Rein and Right Rein (after our halting/mounting practice) and he didn't even ask to leave once! **hugs to my good pony**
I used to train my horses with lessons and lots of different riders. Their manners were perfect. All of my original lesson horses have now passed on, and I don't have the luxery of working them 15 hours a week. So, we work every good weather day we can. It'll still get 'er done!!!
You need someone that can work with the 2 of you. Some horses play little games because they can because you let them. She needs a constant command and lots of work so she learns what is expected each and every time you saddle her up and ride her. She will come around but her "bad" behavior needs to be fixed...Good Luck she is a beautiful horse