How can I convince my parents to let me try horse riding?

I am a 13 year old girl and have never really rode a horse in my life. I am comfortable around horses and i have watched many youtube videos! =) My cousin rides horses and often tells me how much fun it is. I understand it is dangerous and all, but I really wish i could try it. It is very hard to get lessons though because I live in Edmonton AB and not in the country. I do SOOO many sports and my schedule is almost full. I am not looking for a life long riding stable, just 2 or 3 lessons. I haven't even told my parents i am interested yet, and i dont think that they would be very supportive. how can i ask them? and do you know of a good riding stable i could go to near edmonton or sherwood park that supplies the horses and tack? Thanks