have you been working out 3 months your entire life or have you just stepped it up, big difference. I was a freshman @ 5'7 & 160 pounds. I graduated @ 6'2 220 pounds. I had prolly 2-3% less BF as a senior. I ate like a mofo, not always healthy, but I ate atleast 4000cals a day being a 2-3 sport athlete. Lifted on and off for 4 years and not knowing nearly as much as I do now, I made those gains, although im sure most of that just came from growing 7 inches.
Moral of the story, be patient, if you aren't competing in a sport (ie football, lacrosse ), then theres no rush to get big and strong. Keep reading the boards, ive learned more here in 3 months then i did in the previous 4 years & 9 months of lifting.