I'm not going to get on you about starting a cycle at 19... I did my first at 20, but I was also 220lbs at the time. But what done is done.
Clearly your gear is good to go, but I have serious bouts about your caloric intake like everyone else. I am 240lbs with ~12% body fat and when I eat 5k calories a day, I start to gain unwanted body fat on top of the lean mass I'm looking for.
How tall are you??
If you are really concerned about gaining weight and getting in enough calories, I would recommend hitting some dirty calories 2x a week. Go to McDonald's, get a couple Big Mac's and a large milkshake and go to town. If you add 2 of those meals a week, you should be gaining a pound a week (3500 calorie surplus).
Your training is also fucked up, look into Westside Barbell, 5x5, DC, or something else low volume/high intensity.
How many mg's/wk of each compound are you running?? From what I can tell, it looks like you're running 200mg of Test and 300mg of Deca per week. If this is the case, you shouldn't have any issues with libido.
DO NOT use Nolva during your cycle or at any time in which the Deca is still active in your system as it can aggravate any progesterone related gyno you may be experiencing.
Your "just because" is answered above.
If you mean Adex, he would want to take .5mg/day which would be a standard dose. For Aromasin, which I think you mean, you're correct.