I think you are about the youngest age I would consider starting gear. 21-22, still a little young. 

My suggestion would be to keep your cycles shorter for now, making the most out of 8-10 wks on and take plenty of time off between cycles to recover. Part of the concern people will have, including myself, for a younger guy getting on gear, is that (no offense), younger people often aren't known to be the most responsible. I've been 23 and I know what it's like. I'm not saying you are irresponsible. I obviously can't make that call, but a lot of guys your age have some learning to do. These are powerful hormones and once guys get on them, it's human nature to want to stay on and keep moving forward. You have to be smarter than that, and still cycle off. Being responsible also means finding a Dr that will monitor your blood work. You should get your test levels taken before you cycle, so that when you come off, and think you are recovered, you can know for sure. 

I'd also start light with gear. 300mg test will give you some great gains, if you have your diet in order. I put 25 lbs on a guy using 250mg EW, not that long ago. Keep your starting cycles small, so that you give yourself room to go up later. If you do 300mg for 8 wks, followed by PCT. Then next cycle, move to 400mg. Then down the road, when you are ready for a 3rd cycle, maybe do 400mg test and 200mg deca. With each cycle, you should be able to make some good solid gains. 

Remember that even with gear, this is a process. You'll still need years to reach the physique of a massive bodybuilder, and that is assuming that you continue to work on improving your diet and training along the way.