My horse bucks when I canter, help!

Question
Hi, my name is Kayla and I have a 12 y/o QH/Paint mare named Ruby.
I am 14 years old and I have been riding since i was 5, and jumping since I was 8.
I recently bought Ruby, who was used only to be bred.
Anyway, I have the walk and trot down without any problems, but when i ask for a canter she will buck me off or put her ears back and stomp her feet. And my riding instructor keeps telling me to push her forward, but she will try to throw me even more. [plus i am holding on for dear life, both feet out of the stirrups]
I sometimes use small spurs, which she will throw me if I use them.
And I use a whip.

I have had other people try to get her to stop bucking, but nothing helps. and I have tryed to lunge her to get all of her excess energy out, nothing works!:(
Whenever shes put out, she is put with another Gelding.
And she is kept in a stall most of the time, let out when it gets warm.

[my instructor also says I have 3 things going against me, that shes a mare, that shes red, and that she has spots. is this true??]

Answer
Well I don't agree with your trainer at all.  Her color or sex or spots has nothing to do with anything.  Ruby is smart and does not want to run.  It may be lots of things that cause this, pain, bad saddle, she is not ready, she has not had enough training, you are not giving the right cues, spurs and whips cause bucking, this horse has not been given the right foundation, the horse is scared and does not trust you, the horse does not see you as a strong leader, the horse is sour to running, and many other reasons.  You need to work on you and your horse will get better.  Bucking is a problem where you can get hurt, so without seeing you ride and seeing this happen, I can't really help.

But I can say that the more you learn about horses and the more you understand them the better you can help your horse.

Read my horsemanship page and it will help you see the world as your horse sees it.  Horses see things much different than we do as people.

Rick