At what age should I start singing?

You can start singing at any age but children typically start between the ages of 7-9

How many days a week should I practice 

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. 

How do I warm up my voice before singing?

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.