This happened with my aunt and cousins! My little cousin was a "whoops!" baby, and a surprise for everyone since we were sure my uncle wasn't going anywhere near her.. and because she was so large I'm sure nobody thought she could actually conceive.  My older cousin was 15 when her sister was born and was forced into raising her, basically. It was fucking sad. I was 10 when she was born, so to me, my cousin was so cool and mature.  She was fucking 15.  Oh, and my uncle just hated everyone and life so he didn't help much. When my cousins were 5 and 20 years old, the elder cousin passed away due to a rare blood disease or something. Her mother had a heart attack and died less than a year later.