Hey man, I'm 25 and I'm in the same boat as you. I have legit low T. Mine came in at like 350. Got it tested again and it was 375 so that confirmed it was pretty low.
I've been getting injections now for 3 months.
My first few injections I didn't feel a whole lot different. But now each time I inject - the next morning I'm like... "Buzzing." It's hard to explain, I just really feel "naturally" energetic, awake, and I POP out of bed in the morning.
The only tough thing is battling my uncontrollable raging boners in the morning and trying to hide it as I walk into the office lol...
But yeah you're making the right choice as far as staying away from the gel. I went to a testosterone replacement therapy (TRT) specialist and he gave me a shot right there on the spot and I've been on T ever since.
Let us know how it goes man. You'll probably have a bunch more questions. I've found this forum really helpful these past 3 months since I've been on T.
As far as your upcoming appointment, the best thing you can do is describe your symptoms and tell the doc how it's affecting your life and tell him flat out you want to try TRT.
Tell the doc that another doc. was going to put you on the gel, but you'd rather do injections because blah blah... This will lower his resistance knowing another doctor has already considered treating you for low T.
As you know, you just need to find the right doctor. I didn't get a prescription until I went to my 3rd doctor. The first 2 were Endo's which are pretty much worthless. When I finally talked to a testosterone replacement therapy (TRT) specialist I got the prescription. So hopefully this guy listens to you.