Answer

By Your Horse

Natural Horsemanship Expert Charles Wilson says:

Once a horse has learnt to pop over any kind of fencing, it is a habit that is hard to break. I take it that the electric fence was high enough? Any fencing would need to be at least 3ft 6in. It would be worthwhile to replace short posts.
An alternative would be to have 4ft long wooden fence posts with tape passed through rubber fittings. If yourfilly can jump that, you will have problems – but you’ll have a brilliant show jumper!
I get the impression she is an intelligent girl, with a bright mind that needs occupying. Take her out for walks around the countryside, or train her in the arena to step over poles, rugs and tarpaulins etc. All these things will help once she’s backed – she will be a more confident ride.
You could also take her to local shows. Every bit of handling will give her food for thought in the field.