I remember when I was 18, 6'0 and 165 lbs and first came to this website. Fast forward a few years and I'm 195 lbs of pure muscle.
Throughout that time period, I've mostly done HST and 5x5, but I've also thrown in some one bodypart per day routines. I'd say start on the single factor 5x5 program as soon as possible and fix up that diet!