I will be starting next monday, and i am currently trying to gain some height by doing stretching exercises. Will this P90x program help me increase my metabolism and make me taller , i also do not want to lose weight, my goal is to gain muscle mass and just lose the abs fat . Currently i am not very fat or skinny, just average, my goal is to get a little bigger and gain a 6 packs abs. Please help me with some advices so i can accomplish my goal. Thanks you

Stretching and yoga can help with your height a little bit (google this), and I think most people think weight lifting stunting your growth is a myth, but I'm not physician so I can't say for sure about that.

If you want to grow taller the only think I'd recommend is make sure you drink plenty of milk. Your body needs the calcium to grow. Now, (not a doctor) I believe though that your body is going to grow to a certain height regardless of what you do unless you do something to stunt it. I don't really know if anything that will help you grow taller. Lifting weights 2-3 times a week isn't going to stunt your growth, lifting twice a day 7 days a week might.

P90X isn't bad for you to do, even while still growing. However, you need to make sure you get all the nutrients you need to cover your natural growth and p90x, otherwise it's possible you'll become deficient and growth "could" suffer. In the end though just make sure you're not starving yourself, take a multivitamin and drink a couple glasses of milk a day.