L-Arginine and young people

I am in my teens and this suppliment caught my eye. I have done some research on it and heard a few talking about the age you should not take it before. So I tried to look into why you shouldnt take it too early and found out something about a growth horemone that teens and young people have already that it increases. I was wondering if the reason, if there is one at all, not to take it too early is because this growth horemone can be increased too much? I also hear you should be carefull and not rush outr and buy any old L-Arginine supliment and that you should read the other ingredients and make sure they have done ample research etc… so anyone done that or is that just something you dont exactly need to worry about.