Don't worry about what other people say. If people say that your buying her was mistake well, do not think that.
I got my first horse at 12, no one in my family knew anything about horses except my uncle but he didn't speak English and I didn't understand the language. What were my parents thinking buying a young 2 year old filly untrained never had a person on it and then gives it to me who has never ridden a horse? Well we were all ignorant and I wanted a horse. :p I got one. I never fell off of that horse and I learned a lot from her. Maybe I was lucky but have to say the horses are the best teachers.
Sure you don't have all the experience and training but you got to start somewhere and be safe. I can understand having your confidence knocked down, the second horse I trained was a colt and I fell. What I did was like what others are saying start where you are comfortable. Ride a horse you feel good on and if you have lessons judging by your last post, make use of them. Maybe spend time with your horse, you don't have to ride her just yet if you are not comfortable but just get to know each other and build your relationship.
Wish you luck.