You could call them, and say that you messed up but are really sorry and want to fix it, you just need the right materials. They'll likely appreciate your honesty and maturity in fessing up.
You could start training him now by getting him accustomed to having weight on his back, basically turning him into a pack-steer. But, he won't be ready to actually ride...
Tell your family to keep your identity private so that nobody tells your dad. Make it clear that you don't want your father to know that you are bisexual by...