Alright, Choppa, I can't rightfully bust your ass then bail out on ya when you address me specifically. Where to begin? I'm just gonna let fly in no particular order as I'm on a phone...
Yes, 21 is pretty damn young to be messing with this stuff. Sure, guys your age have done it and done it successfully. Mainly due to:
1. Luck
2. Good mentoring
3. The utmost respect for the hormones, what they're capable of both -/+, motivation in research/knowledge/understanding that rivals their intensity in the gym.
The most reliable person you have in all this, when the needle hits the skin, is YOU. It's you based on hours of reading, well thought out questions that are, hopefully, verified by solid vets. Honestly, in this day and age with what's available, you could lay out a decent first cycle, where to get pins/ancillaries and good PCT w/o asking a direct question. Anything you could be asking at this point has been answered thoroughly and correctly. You could be fairly fluent with just about everything you need to know about running a Test cycle in a few weeks of STUDYING 2-3 hours a night.
Yes, 900mg of Test is a hefty, hefty dose at age 21, 174lb. That's 99% chance of excessive estrogen on that dose. Four hundred would be a much better starting point to get in the game. Do I think you should drop to 400 now? No, I think you need to get yourself off and straightened out. You've got some issues going on from the PH cycle and dropping 900mg, or any mg of test isn't the fix right now. You're gonna do them, you've said as much, so I'm not gonna play holier than though and tell you not. I would advocate going back to the starting line before you get too far down the wrong road.
I would look to the PCT thread and come up with a plan. You'd be looking at the gist of that beginning approx 2wks after your last 2 shot. Perhaps Dylan, RickRock or Steve could tailor something suited to your particular timeline concerning the PH and now test. As for your bro taking good care of you. Tell me has you hooked up w/something for estrogen control
I'm not trying to talk you off the gear. I don't advocate, at this point, but it can be done and done safely with KNOWLEDGE and the WISDOM of those experienced. Congratulations! Plenty to be found on this board. I've been on a ton of boards over many years and you've got some cats here that can flat deal.
From my experience your best bet is put the time in to understand a beginning test cycle, formulate that cycle, ancillaries and PCT, then present it to the board. Plenty of good bro's are happy to put the finishing touches on a proposed cycle
Before all that, get off, get PCT'd up and get back to a dr. That Vit D red flag should not have been ignored. Reel yourself in, get things tightened back up and you should have a fair amount of Test left over when you get things squared away.