I'm inclined to agree with those who have advised including the Mrs in the process - at least to begin with. My wonderful spouse came to my first few endocrinology appointments (as well as attending therapy sessions with me), until she tired of how uninteresting they actually were and realized that there was no need to be worried or suspicious of my therapist and endocrinologist.
Reschedule (once). Two weeks is nothing in the grand scheme of things, although those two weeks will feel like two years. Discuss beforehand what you're going to say to the doctor, what you're going to be asking for, and make sure that she's okay with that. You two need to be on the same page before you walk into the appointment - there is no room for disagreement, surprise, or uncertainty in front of the doc.
My wife and I went over how things would go that first time. Although I would have asked for a transitioning dose immediately, we had agreed that taking it slow was the best plan to begin with. We both knew what I would be requesting in terms of medication - a conservative dose, then ramping up over time (incidentally, the standard way my endo did things, but we didn't know that beforehand.) And it went well - she was not surprised by anything that came out of my mouth, the endo highly appreciated her being there and asking questions, and everyone was happy.
Keeping my wife involved in the process removed any sense that I was working against her, acting secretly behind her back, or excluding her from my life in any way. Having a supportive spouse is wonderful, but it also requires maintenance. Each one of these steps in transition - coming out, therapy, first endo appointment etc. - is a huge change in the relationship for her, and even though we tend to think of these milestones as exciting, spouses are often extremely worried about what the future will hold as transition progresses and becomes an increasingly physical/medical undertaking. Make sure that you let her be there - not just so that she can support you, but so that you can support her.
Of course, if it does turn into a clear stalling tactic, then the discussion changes. But give her the benefit of the doubt.
All the best. It'll go just fine.