I have the same problem I had my littel boy when he was just 3 the best thing so he dosn't distract is that he keeps he's attention in you i mena you can do alot of different ejercises like circles or trot and stop and then trot and gallop and so. I know It's not easy but with time you can doit and think that she is just 6 It's the age to look at everything and play with everything she's just a baby 💖💖 good luck !!
Alot of horses go through the "fear of the leg" phase It's normal.
First of, just because your horse gets stressed when you use your legs doesn't mean you can't use them quite the contrary you should use it more, they will just have to get used to it, its also important that your horse knows that your legs aren't just used when you want him to go forward he also haves to learn that your legs can be also used to ask for bending or yield he needs to know the differences between these aids (foward, bending yield) but make sure you know them aswell!