well everyone that i know took it at 17 and they were perfectly fine so thanks.
Take some advice from a 20 year old. Stay on the forum and read and ask questions. If you just put in some time and try to learn as much as you can about training and nutrition you will probably decide for yourself that you don't need PHs at this time. Trust me, there is enough information on this forum to read for hours every night if you had time.