Mine happened after I was about 2.5 years on T. Prior to that I had a lot of trouble seeing myself as male...I knew I was supposed to be male, but I just didn't have the confidence at all. I was convinced people could always "tell." I had a lot of bad experiences for many years regarding transition, where it was delayed, and even the most supportive and well-meaning people were hurtful. I also had flat out abusive experiences. So those tainted my view on everything and I always saw a woman in the mirror despite the time on HRT. I was deeply unhappy because I felt like I'd never be able to be seen as the man I am, live fully as a man, or see a man in the mirror.
But then I started a new job and was seen as male without question. And quite literally, I had no qualifications, lol...other than life experience and a great deal of passion for people. Management took me at face value and gave me a chance, putting a lot of faith in me and a lot of responsibility into my hands. So I have always felt grateful to them for seeing the worth of my convictions. In turn, I had to become the type of man that I felt the job required. In terms of seeing a man in the mirror...well...that just took some time. Realizing that people saw me as cis and I did not have to out myself unless I wanted to, ever. When I did out myself to someone, she was surprised, but extremely kind and accepting (despite her ignorance in some regards). I also had to out myself to my boss, who could see that I was upset and told me that I did not have to worry about anyone knowing unless I wanted them to know, because my experiences were only something that made me wiser, not something that was written plainly for others to see on my face.
And I just remember one day that I looked in the mirror and I saw a man's face, the face that everyone else saw. And since then I have never seen "her" at all. But it was more than that. I looked into the mirror and I saw a man who had stepped up to the plate, taken responsibility, who values what he does and respects and loves the people he works with and for. Who has a painful history but no longer has to be defined by it. That was such a euphoric moment because I never thought it was would happen. And it was thanks to the people in my life who were able to see my worth when I felt the most worthless, and the people who were able to love me when I was feeling the most unlovable.