if i were you i would start saving some money and buy something new when you can afford it. i bought my first compound bow at 11 years old saving allowance hahahaha. keep in mind that if you buy something used or cheap it will either a) not fit you well or b) be a piece of garbage. no need to start at the top but find something that is going to last.
i found picking out my own bow only grew my knowledge and interest in the sport.