Long ago I used to bully a girl in school. Years later I find out she's depressed and has had suicidal thoughts.
That's so unfortunate. Why did you feel the need hurt her?
She annoyed me and I didn't like her appearance.
That is still no reason to be a bully. You should be more kind to others from here on out. Your words can have a lasting impact on people.
Why should I have to feel guilty, I was just having fun after all?
Can you try to think of how she self being depressed and suicidal while you bullying her? It can be very devastating, would you want to be responsible for her death? I think it would be best to try and just apologize and acknowledge your wrongdoing, to give closure to both of you.