Hey Devin,
Congratulations on the scheduled consultation. If you've been reading posts on here for a while, you've probably got a pretty good grasp of what happens when you start taking testosterone. The very fact that you're trying to make a list of intelligent question shows that you are serious and you understand that hormones are a big deal. Your doctor will probably go over with you the common and uncommon effects of testosterone. My endocrinologist had a printed document about effects and warnings for me to read and sign. I was so eager to get started that I didn't ask too many questions.
You could ask how often they'll do blood tests to monitor your hormone levels. And how long after you begin until they expect your levels to be on par with those of an average male of your age. For example, my first repeat blood test was 1 week after my 3rd injection. The results of those tests showed that I am still below the minimum level of total testosterone for an average adult male, but the doctor has not yet increased my dose.