Can anyone give any suggestions?

[cupcakes16]

Hi everyone! . Can anyone help?. I have a Welsh D X TB, 5 years old, mare, i ride her in just a plain loose ring lozenge snaffle, When i ask for canter she shoots off into a bolt sort of thing, she has had her back, teeth and saddle checked (everything ok.) She is fully clipped, up to date with everything, when i half halt her she tends to leap into the air and go faster and just ignore me completly? So i have to just use my voice to slow her down and seat for ages until she comes back to me, She has been doing this for just over a month now. It's always when you ask for canter, What could this be? is it her age? change of weather? or is it her just being moody? I have had her since she was 2 and backed her myself, If anyone can give me any advise that'll b​e great, thankyou

 

[Hoofing-it]

Hello from a fellow east midlander! You may be better off posting this in the tackroom rather than regional forum for a broader spectrum of advice, but here are a few thoughts....

Is the horse fully sound? If not, cantering may present an undesirable imbalance for the horse causing pain? Does this happen on both reins? Is your horse sensitive behind the girth area for some reason and your canter aids are causing pain?

I hope you manage to get sorted!

 

[Hoofing-it]

Just re-read: your half halt comment suggests that it might be worth having her teeth looked at if you haven't already?