I've been undergoing HRT for the past three months, but I've found myself starting and stopping the program repeatedly. My desire is to achieve a more feminine shape, but there are moments when I hesitate. 

I often find myself resuming the treatment for a few days, only to pause once more, then after seeing before-and-after transformations of others I start again. Has anyone else experienced this uncertainty? If so, what helped you maintain consistency and overcome the challenges?

No uncertainty for a moment, but I have much difficulty forming routines. What helped me the most was to start keeping a diary in which I mark everything from HRT to NBE to pumping and other stuff. I started to make it into my daily routine that I update the diary every time I do something related to HRT etc. and then just force the habit. Once I did this long enough, it became such routine I follow almost obsessively. I get really anxious if I miss marking down something.

So my suggestion is a diary, on paper, your phone or computer, what ever is the easiest. Then take it as a habit to mark things down every morning the moment you're awake enough. Then repeat before sleep if needed and never start your day or go to sleep without. It takes some effort but after a while it becomes a daily routine. For me it takes a lot of mental work due to my ADHD brain being all over the place most of the time. Its been fantastic aid on remembering all details for the last three years.