Please, please, please use Signal instead. And tell your friends!
Telegram has made very dubious privacy claims, but even if you trust the company, Signal has a far superior user experience. Telegram’s private messages are not enabled by default, and when you are using private messaging, numerous other features are disabled defeating the point.
Signal on Android relies upon Google Play Services for the microphone and camera permissions, which can't be turned off.
It is open-source [1] so one could install it without going through the Google Play Store (it's not on F-Droid though), but it's another case of Google's ever-expanding grasp over "interesting" (read: competing) Android apps.