I've been debating whether I want to go on T or not. I really want most of the changes but I've heard that it can ruin your singing voice, or at least take a lot of retraining. Singing is a really important part of my life. I've been working at it for years and I've just finally gotten to where everything is starting to click together. I really don't want to have to start over. I think I can live without hormones, it would be nice but I can work around it. The only other problem is acting. Again, this is a really important part of my life that I plan to continue at least on a community level throughout my life. I have been able to get male roles so far because there aren't usually very many guys who audition for the troupes I've been part of, and because my body language is more naturally masculine and that's how people tend to read me when I'm acting. But my speaking voice is higher than most adult males and that combined with my height (I'm 5' 5", I can fake being a little taller with boots and hair gel but not much) I'm worried that I won't get those roles anymore. It's not that I mind playing female roles, I wouldn't, but I'm not very good at it. The few times I've auditioned as female I haven't been convincing and ended up getting cast in male roles anyway. Sorry, this ended up being more ranty than intended. Any advice is appreciated.
Just keep on practicing warm ups even when you start T. As long as you warm up your voice, even if it changes, you're still training your throat. The vocal memory may change, but it should not be impossible.
Practicing can help strengthen your vocal cords. There are many people who are musicians and on hormones, and their singing wasn't harmed. I think with some people, their voices after starting T aged like fine wine, and they sound amazing.
There are lots of FTM singers. I think you just have to relearn the way you sing. You're basically a young boy whose voice is dropping. It will certainly take some getting used to, and you might have trouble singing at all for the first few months. I love to sing myself, though just for my own private enjoyment. I really couldn't sing period for about two months. I don't want to scare you, but I've lost a huge amount of my range since starting. And my voice dropped a lot lower than I was expecting. I was a soprano and I'm now a baritone. And can barely hit some of the higher baritone notes. My range before was E3-E6 and is now F2-D4. I can only sing about five notes in head register now, it's really weird as a former soprano. I imagine you'll have a better time retraining yourself than me if you have real vocal training though. I must say, although I love having a lower speaking voice, I sometimes get a little sad that I can't sing any of the old parts I sang before. Now even if I sing along to the radio, I have to sing most songs with male singers a whole octave lower and songs with female singers two octaves lower.