The only friends I really specifically remember telling were the ones who are also trans. Like you, I also felt a little weird talking about it, so it was a lot easier to tell to people who I knew would have the same level of understanding. But no one else ever questioned me as the changes started happening, which I never even thought about until now. Looking back, it is a little weird that my friends weren't as curious as I'd expect most cis people to be. I definitely got comments on my voice dropping and noticeable things like that, but nobody asked why or tried to inquire any further than that.
As for someone to talk to, if you're worried about being uncomfortable bringing up the topic with your friends, you might want to look and see if there are any support groups around you, that way you can get several different perspectives on the experience. You might also consider seeing a therapist if you aren't already, which will definitely help when you're first starting T and having to deal with all the changes not just physically, but socially and emotionally.