Hi! Welcome to the Horse Forum.
It does little good to just start over and over and over. Horses have a problem with one lead because they have a problem with stiffness or with proper position of a certain part of their body. You also need to make sure the horse does not have a lameness or soreness issue.
Instead of just starting her over, why don't you try getting her more flexible and get her yielding better to leg pressure and rein pressure?
I would start by teaching her to yield better to the bit and to become more flexible in her body position. Using a snaffle (two or three piece), ask her to lower her head, bend at the poll and slightly tuck her chin. When she is soft in her face, start asking for increasingly smaller circles at the jog, particularly to the right. Pay a lot of attention to her head, neck and body position. When circling to the right, you should be able to barely see the corner of her right eye. She should follow her nose well enough that you do not have to pull steady on the right rein. When you do pull on the right side of her mouth, her weight and energy automatically goes into her left shoulder and she will take the outside lead as she moves into a canter.
Build flexibility in her body by teaching her leg yielding exercises. This means you gradually get her whole body to bend to the right using your right rein and your right leg to push her ribs out. I like to track to the left, make a half circle to the left and then push the horse back out to the track with my right leg until the horse is back on the original track but now tracking to the right. I start these leg yielding exercises from about the 4th of 5th ride on a colt.
When the horse 'yields' to the rider's right leg and moves willingly out to the left, ribs first, the rider and horse is ready to learn to yield to the riders left (outside) leg placed further back than the inside leg that is asking for the ribs to move out. This outside leg starts asking the horse to bend its whole body by bringing its hip to the right. So, you will have the horse's head bent slightly to the right, your inside (right) leg is pushing at the girth to push the horses ribs and shoulders slightly out to the left and your outside (left) leg is asking the horse to keep its hind quarters in and following its front feet and nose. [This body control exercise also stops a horse from dropping its inside shoulder.]
When you can attain this kind of body control of the horse, ALL lead problems will completely disappear in a sound horse that is not hurting somewhere.
Something else plays into getting the lead you ask for, particularly in a green horse; that is the place that you ask for it.
If you jog a big circle, you are much more likely to get the inside lead if you ask for it in the far corner of an arena when you jog toward that corner. This is where you know the horse would rather go to the other side nearer to the gate, the barn or his friends. When we lope green horses that do not have all of the body control of an older horse, this is how we get the correct lead almost 100% of the time, Then, as the horse gets more 'broke' and we have more body control, we can start asking for the correct lead and getting it anywhere in the arena including the near side of the arena and the straight side where there is no curve or circle to help us.