I have been weight training/lifting since October of last year. I have seen results from my legs ( My thighs can move an extra 50 lbs than before ) but my shoulders and arms do not seem to have really improved. My triceps feel stronger but my biceps are still thin ( in width ) and weak. I'm almost 14 and that makes me scared because I want to have stronger muscle than I hqve now. I will admit I don't work my upper body as much as I have my legs but I have for a few weeks. Any tips on getting them stronger ? Should I take more time and just wait ?