ok, here is a workout plan for mass. You will have to google the technique. Split your workout so you are doing weights 4 days of the week, jiu jitsu 2 days, rest 1 day.
gym day 1 - chest = flat bench, incline bench, close grip bench and skull crushers
day 2 - legs = squat, lunges, romanian deadlifts
day 3 - back = deadlift, row, wide grip pull ups, close grip pull ups
day 4 - biceps and shoulders = military press, heavy barbell shrugs, arnold press, straight barbell curl, front grip barbell curl
go heavy and use full ranges of motion... be carefull witht he weight on the squats though because of your age