Hi Jenny, I just wanted to say that I'm right there alongside you. You summed up my thoughts exactly in that I picture a future as female, and that being male just feels like standing still. The problem is that standing still feels alluringly safe at times. I have a hard time putting a percentage to my "sureness", though it's certainly not 100% by a longshot.
My confidence in my decision is undermined by stray thoughts constantly... I think things like I'm fairly attractive as a male, I could have a solid life, a solid future. Maybe not the life I want most, but a safe life where I don't have to fear being murdered by a date, laughed at or ridiculed. Where I don't have to fight for jobs, insurance coverage over medical bills, and pretty much everything else. A life where I don't have to have what that particularly dreaded discussion with family... Despite those thoughts though, I know that I'm pushing forward towards starting HRT regardless. I even originally wanted to lose more weight first and start at the beginning of next year, but I am feeling more and more like I can't wait and would rather suffer weight loss while on HRT.
And while we often share similar experiences here, we of course think about things and approach them differently. So I don't know if this well help, but on the off chance it does, here is my thought about why I am pushing forward to HRT despite the doubts. I tend to be an analytical person, and my reliance on what feels like logic has gotten me into trouble. It has led to the path of least resistance many times over, doing the safe thing over the gamble. I've used logic essentially as an excuse to put things off indefinitely, including dealing with this issue. So this time I've tried to look at things in a different light, even if still logically, and try not to reason my way into cowardice again. Instead I am pushing myself by using said logic to go for the gamble and set whats "safe" to the side, because like you I am sick of standing still. This all hinges on a few simple things, one leading into the next...
1) Even if I'm unsure of transitioning, I'm definitely transgender.
2) All of the wonderful men and women here who have more experience than I have often one thing in common above all else: Their dysphoria grew. It didn't go away, and it reached a point where they were forced to transition in their 50s, 60s, and maybe older in some cases.
3) Even if my dysphoria is manageable now, and "staying male" is "safe"... Shear numbers say this will most likely not continue to be the case. So why wait? Why wait until I'm approaching 60 and I'm at that inevitable do or die moment instead of just biting the bullet and getting it over with? Because as scary and unsure as I am about doing it at 35, I'm far more scared and unsure about doing this at 55.
4) So essentially... I have my answer and my confidence in my decision despite my not being completely sure. At times maybe not even the 80% you say you have. But I firmly believe that doing the easy thing, the safe thing is a siren's call, that can only cause me heartache in the end.