I am 17 years old and i go to the gym frequently and was wondering if creatine was bad for you because i have been taking it for 3 months?

Use moderately: Creatine, as an added protein source to help build muscle, is generally safe in moderate amounts over a limited period of time, 3-6 months. It is a good idea to get blood tests for liver and kidneys to make sure you are tolerate it well.

Creatine.: Creatine in doses of 1000 to 5000mg daily has been shown to increase muscle mass, muscle size and muscle energy stores. Creatine must be taken with lots of water throughout the day, and doses must not exceed 5000mg daily to avoid impairment of kidney function. The dose can be taken all at once, preferably after exercise to facilitate ATP store replenishment in the muscles after exercise.