Andrea had been driving her little sister, Amy, back to school when the zombie apocalypse occurred. They were saved by Dale and have lived with him since then, and don't know what happened to their parents.

Andrea had to shoot her sister in the head after he was killed by the zombies and resurrected. She carries the guilt of shooting her sister, and feeling like she had been a bad sister before the apocalypse with her, and if it weren't for Dale, she would have committed suicide by staying in the CDC when it was about to explode.

The Walking Dead Quotes

You can breathe. You can blink. You can cry. Hell, they're all gonna be doing that.

Negan

In case you haven't caught on, I just slipped my dick down your throat, and you thanked me for it.

Negan