EAT EAT EAT... You can chow on 40-50lbs so easy @ your age.
Do it while you can! A little fat has to come along for the ride to
gain muscle. Nobody makes gains like a Frank Zane in contest condition.
Its a fantasy. If you want size, got to get a little fat.
Just till you start to lose your abs.
Can allways rip it up later.