Everything was fine till today. Now I turn the key and nothing. Battery is good. No previous starter problems. It just seems dead when I turn the key. The theft system light is on and I tried the key on for 15 minutes. Suggestion and the light never went off? Can anyone help?

The Anti-theft system,likely disabling Starter, and needs to be disarmed, repaired, replaced, or bypassed.
Double check shifter position, maybe move around to Neutral.