1. Don't do juice. you have no base.--don't take prohormones either- and don't go out and buy a mass gainer.
2. School isn't an excuse- I'm a Pre-Med & Finance major working 20+ hours a week n keeping great grades-still find gym time.
3. It will be important for you to keep a solid diet that YOU STICK TO DAY IN AND DAY OUT!--This is key man!
4. Routine wise-- before you were doing the typical upper body only workout- I saw that you are switching to include legs---good! they are the foundation!
I would do something like Upper/Lower 2x a week since you are a beginner-- 4x a week you are in the gym-- Make it count!
Upper-
Bench--3x5
DB Incline- 3x6-8 reps
OHP- 4x6-8 reps
Dumbbell Rows-4x8-12 reps (focus on back working
Pull-Ups- 4xmax
Lower:
Squats-3x5
Stiff legged DL- 4x6-12 reps-use 25lb plates to get a better stretch and don't go too heavy, no need to show off
Lunges- 4xreally far
Upper:
Overhead Press- 3x5 reps
DB Flat Bench-3x6-8 reps
Lat Pulldowns- 4x8-12 reps
T-Bar Rows (or any sort of row really)- 4x6-12 reps
Rear delt flyes-4x12+ reps
Lower:
DL-3x5
Front Squat- 4x6-10 reps (keep tight form)
Leg Curls-3x8-15 (don't jerk weight up)
You'll notice there's no direct arm work--build a base first and get some respectable lifts--then worry about the guns. (if you must--throw in a few curls n pushdowns on upper days-not necessarily both days)
Diet wise--Whole foods. Turkey, chicken, beef, fish, nuts, greens, rice, olive oil, greek yogurt, whole eggs. --make these the cornerstone of your diet. The occasional burger won't kill you-you're 21, live a little.