Test first cycle is a good start and disagree with adding deca for a first cycle - keep it for cycle 3 imo as you'll get great results with just test. Best results with as little gear as possible ideally

HCG and your pct is good, 2 weeks after last jab for pct meds.

Glutes and quads are my preference, then shoulders.
Exchange supplies is where I get pins, wipes and syringes etc

Make sure your diet is on point for your goal if you want to make the most of this cycle - makes a huge difference.

There are plenty of potential negative side effects, TRT is given when the cost benefit is in favour of TRT. But those are potential not the ones you'll get - that vaires alot person to person.
As long as you can justify any potential side effects and the cost benefit, go for it! You don't need anyone to justify this for you.
Reality is one cycle will imact your health negatively VERY little! If you're really bothered, get some bloodwork done before you start, mid cycle and end.