Hey Natanat,
I'm also 24, so perhaps I can relate with your fears. I too get scared about whether or not I will pass and wonder about my future. As many of the above posters have said, we are children compared to a lot of other trans women. This doesn't always play a factor as hormones are unpredictable, but we are in a good age to start. Nothing is perfect and you can't go into this with false expectations; however, it is possible to have a very successful transition. Just don't hope for the impossible, like your bone structure changing and make sure you learn about what hormones can and can't do.
At the moment, my experience has been positive, but has left me wanting so much more. While I have been on for only a little bit, I am happy by the changes and also upset that it's taking so long. I'm progressing, but not as quickly as I'd like and still feel uncertain about things. Therefore, please realize that it's a waiting game and easy to get impatient while you are in the midst of it due to the time frame and unpredictable nature. As for passing potential, I don't know what to say. In my case, I do believe I will pass one day (at least I hope), but I do get scared and worry. To be honest, I think the hardest person to convince in our transition is the most important person, ourselves. Even if I one day pass in the eyes of everyone else and am viewed as gorgeous, I still need to pass in my own eyes. That's hard
to do because we are the most aware of our flaws and we can nitpick anything that isn't 100% feminine. This is something I have to learn to work with.
I wanted to share my experience because you are the same age as me and seem to have the same fears. Because I can't fully answer your question, I wanted to at least share my experience so far and hope it will help you in some way.
Good luck with everything!