It seems that you really do love horses
and are passionate about riding
and taking care of horses! I do not know your mother's reasons for not allowing you to have a horse at this time, but perhaps you can talk to her and understand her point of view? having your own horse can be VERY expensive. Not only the price of the horse, but the board, the farrier, the Veterinarian,. any medical expenses, your riding lessons, your tack, riding gear, etc. Maybe this is the reason? Also, about time..