Is 21 to late for mma /kickboxing/muay thai?

i am 21 years old and i dont really have any experience in mma and kickboxing but the grandmaster at the gym told me it was to late for me to get into some amature fights, what do you guys think?? i think im still young enough to train and compete in a couple of years but im not going to sign up to a gym where the grandmaster says its to late for me