I was on Rogaine for a year and it did nothing for me. It seems to have worked for some people though, but as you stated the reviews behind it are very mixed. The general understanding is that if your male pattern baldness started very recently (within the last year or so), Rogaine can often bring back some---but not 100%---of your lost hair. If you've lost your hair for two years or longer, more often than not that hair will not grow back for a lot of people. There have certainly been success stories, but it seems they are often the exception rather than the rule, just like successful voice feminization surgeries.
I outweighed the pros and cons behind Rogaine and came to the conclusion that further use of the drug is simply not worth it for me. Having to deal with greasiness for periods during the day, having to schedule your showers around Rogaine (you can't shower within a few hours of using it) rather than being able to shower whenever I wanted, having to be a slave to the expensive product most of my life and having to commit to it big time... all for very little return and benefit. So I decided to stop.
My advice for you is to simply prevent any further hair loss. Another alternative to Rogaine is people take finasteride/propecia. Propecia doesn't promise to grow back your hair, but it does prevent, or at least dramatically slow down, the hair loss process. Trans women on HRT are often prescribed that same drug too in order to battle DHT and testosterone levels, so it works out!
Edit: Also the good news? You don't need to have visited a gender therapist or be approved for HRT to start Propecia. It is typically prescribed by endocrinologists for any genetic male. You can ask your endo (or even dermatologist, that's who prescribed it to me actually) to get you on propecia, and you will have effectively also started HRT!
