First off, when you say buddy you really mean you. Just kidding (Sort of), I could not tell you if it's a 3 month cycle because all you gave us was the cc/ml of the bottle. You did not mention the amount of mg per cc/ml...For instance, you could have a 10 cc/ml of test and the dosage could be different. 1 cc/ml could be 100 mg, 250 etc. etc...So, figure out the dosage you have first. 10-12 weeks is a desirable length, so 3 months fit right in there.
You could inject in the delts, thighs, or ass cheecks (Ass cheecks is easiest)...And quite frankly if you're only taking test you should be fine switching off ass cheecks every other shot. I usually only hit delts or thighs if I'm taking a combination of things and especially when I throw in a water based compound like winstrol which needs to be injected frequently.
To figure out where you want to inject in the ass, you can literally draw or imagine a big plus sign on one of your ass cheecks (Splitting your ass into 4 quadrants per se)...If we are looking at the right ass cheeck the upper right quadrant (Pic is left cheeck but you get the picture)
I'm assuming if you don't know about dosages you don't know about post cycle therapy either....Which would be very wise to know. You need anti estrogens on hand before you start.
Lastly, you are to young...I mean your friend is to young. But I figured I would post this anyways because people will do what they want to do I guess.