First of all don't you think it would be a good idea to get back into it for a while before you start to use gear? Secondly, even at 21 seems like your natural test levels would still be pretty high. I would wait six months, see where you end up naturally and then come back to what you need to take if anything. In any event you will know for sure whether you are really willing to make the commitiment to bb.

I have noticed in my gym that when people who used to be in shape come back, they snap back a lot quicker and with less effort than poeple who have never worked out before.