At that age, I don't think this is a terrible idea if you eat enough for it.
As far as a workout program goes, one thing you could do a search for is Big Beyond Belief, which does have a 6x/week twice-a-day program, although that part of the program has not gotten great reviews (the 4 and 6x/week are preferred).
Besides that, though, you really need to lift heavy, eat a lot, and recover. Only do the 2x/day thing if it's convenient for you/you just want to. You would probably do just as well to do once a day and eat like a champ and sleep a lot.