My family is weird like that too. My dad’s oldest sister had my cousin when she was in her late teens so her oldest son is my mom’s age. My dad, the youngest of them was 50 when my youngest brother was born. So we have first cousins that range in age from 53 to 11. And the 53 year old is a grandpa. It was really kind of neat that my grandmother got to be a living great great grandmother. Hell a good fraction of my great great grandparents were foreign born and some of them never even lived here in the US.