I'm 24 and have been on spiro and Estradiol for 2 months with an additional month or so of low dose estradiol alone which I really don't count.
The initial low dose of E did little for me besides change my sense of smell and play with my emotions. The real changes have started since I started Spiro and have increased my estradiol. I still have a long way to go and don't know where it will take me, but I have been happy so far, despite my impatience and desire for a lot more results.
At 25, you aren't at a bad age to start. Keep in mind, however, that hormones are very much a waiting game and can be unpredictable. It's impossible to know how much of an impact it will have on you, but your age is in the optimal range. Good luck!