Aaron Skinner answered 9/2/2011 How Much Should A 14 Year Old Bench Press That Is 5'8 And Weighs 120? I'm 14, I'm 5'8 and I can bench 85 lbs 15 times. I have been lifting for a year but have gained no upper body stregth at all in that ammount of time. I don't now how to fix that. Maybe I should get protein shakes.