When Isabella was a baby

When Isabella was a baby she went to school with me and so did her sister Kierda. When I ask her who Kierda is she says 'she's just my sister'. We have welcomed Kierda because she doesn't cost anything. I'm not clear who Kierda's mother is but I have been told I am her father. Not sure how I missed that. When Isabella was a baby she liked roller coasters but she doesn't want to go on them now. When Isabella was a baby she wanted a dog but now she would rather have a cat, however she won't pet either.