I'll give you my advise lil man. I'm only 17 right now and i use to be 6,1 250 lbs of complete fat. When i was about 14 I began to workout but not heavy training. I got all the way down to 170 lbs by working out and eating right. Now Im weighing 205 with about 10% BF. If you want to get big you must listen to what they told you eat, eat, and eat. It sometimes might even be hard to swallow it down but you must eat it all. Your body burns so many calories a day just from sittin there or from workin out whatever your doing your burining calories, also everyones body has a point to where there body can only burn so many. you need to find out what your body burns and just exceed that limit every day and you should start to gain so weight if not just up it a little more. Eat healthy though not junk food and simple carbs. Eat your grains, fat, and protein. Anu questions just write me