You can start singing at any age but children typically start between the ages of 7-9
Ideally you should practice 15-30 minutes, 5-7 days a week. However always scale back your singing if you feel any pain or strain on your vocal chords.
Below are a few recommended vocal warm ups to get your voice ready to sing:
Yawning – Take in air with your mouth closed and create a yawning sound while letting the air out.
Humming – Try humming a song all the way through to loosen your voice up.
Jaw loosening exercises – Open and close the mouth several times or pull your jaw down until you feel slight tension and hold for 30 seconds then release.