So its starting to seem like I need a degree to even think about starting to inject. I ordered 6 bottles of 250mg Testosterone Enanthate (mostly to test the legitimacy of the seller) but also try for the first time. From what I gather from my recent studies I would be an idiot to use this with out some type of estrogen blocker. What would the risk be if I only took one dose and stopped? Would I incur the same risks as taking it for 12 weeks? Any type of guidance would be much appreciated!

A little background:
I'm 6'3, 25 year old male weighing 225lbs, just trying to gain a little muscle mass and definition. I've been pretty lazy over the past 7 years and I'm having a difficult time getting back into shape. I'm not looking to use for the next ten years just looking for a nice jump start.

Sorry if my question is answered somewhere else, I tried looking for awhile.