While most exercise is not going to affect your growth, there is the chance of damaging growth plates in the long bones with excessive loads and poor movment/technique. Working with heavy loads (1 – 3 RM range) or performing excessive range of motion under load is not advised for youth exercisers. While a highly trained young person with good supervision will rarely experience such injury, why risk it when it has been shown to be no more productive to work in the 1-3 RM load range than to work in 6 – 12 RM range done to safer VMA (voluntary maximal action). I would suggest finding a fitness instructor that works in youth training. And learning how to do it right. Small investment if you take the long view.