Last night when I was ready to go to bed, there was a knock on the door.

ThaIt was my mother, who had some pieces of apple.

"Wanna have some?",

", she asked me.

Since thait was late night, I did not feel like eating anything, and told her that to her.

This is fine, but in casual speech it would be more common to use "didn't" instead of "did not". I think most folks save the full "did not" for when they're trying to be formal, or want to emphasize the "not", like "I did NOT do that" in response to someone accusing you of doing something.

She had never stayed up so late and never didone such a thing before.

Since you use "had" you need to use the part participle, not the simple past. For most English words these are the same, but there are still a lot of irregular ones and "do" is one of those. The simple past of "do" is "did", and the past participle is "done".

The next morning, I asked why she did that, and i. It turns out that she did not remember anything and she said she might have sleepwalked.

Your original is fine, but breaking the sentence up makes it a little easier to read.

Last night when I was getting ready to go to bed/going to bed, there was a knock on the door.

Getting ready to go to bed/going to bed - use whatever one is applicable

ThaIt was my mother, who had some pieslices of apple.

“Slices of apple” is a more natural way of saying this

"Wanna have some?”,

", she asked me.

Since thait was late at night, I did not feel like eating anything and told that to her.I let her know this.

She hads never stayed up so late and has never didone such a thing before.

The next morning, I asked why she did that, and i. It turns out that she did not remember anything and she said she mightthinks she may have been sleepwalked.ing.