Just dont worry bout anyone else but your own progress bro. Remember that everyones body is different and even though youve always been smaller, you can put on some good size and walk around with your head held high.
Oh and dont by fitness mags like muscle&fitness or muscle mag. Just come here and listen to what the people here can tell you bout it.
Also, always remember that the most important three factors to being successful at bodybuilding is as follows:
1. Nutrition. This means eat eat eat and then when your full, eat some more. Since your young and natually skinny, you probably shouldnt worry that much about fat but do not go overboard with unhealthy food either. Plenty of PROTEIN PROTEIN PROTEIN. tuna chicken beef.
2. Intensity. This means that when your in the gym, dont worry bout anything else but working your damn ass off and i promise it will pay off. Of course you wanna train correctly so dont go lifting the heaviest possible weight you can find. But train with a very good intensity to get very good results.
3. Stick with it no matter what! This obviously means that the biggest reason people quit this sport is because they cant persevere and give up. If you just stick through the tough times, you will thank yourself later and it will pay off.
Stick to those cardinal rules and i promise you will see results. It just takes time. If this was easy, everyone would be doing it. Work hard and you can succeed bro