Did you have a major growth spurt at some point? Like a year period of time where you really grew quickly? I know with girls this happens and then after that they only grow another inch or 2. Not sure if it’s exactly the same for boys but I would think it would be somewhat the same. My guess is if that happened to you a while ago you are probably slowing down. I had some male friends who were pretty small in high school and then had their spurt in college.