I decided to never steal again because I feel so guilty.
That's good, have you stolen since then?
No, I haven't stolen anything after I decided not to.
It's very important that we learn from our mistakes, so it's good that you realized that stealing is wrong. It's always okay to make mistakes so long as we don't keep making the same ones over and over.
I noticed how much I hate it when people steal my things.
That is a smart way to think about it, good job improving yourself and learning from your mistakes. Just be sure to keep it up and remember the lessons you've learned!