I’m also the baby of 3. All girls. I was an only from 12 on, but it seemed longer cause I was the only one downstairs. Both of the sisters had their bedroom upstairs. I loved being alone. I don’t know where my sisters were, friends houses? my oldest sister probably moved out already, but starting age 8-9 I was left in the house alone for Labor Day weekend. I watched the jerry Lewis telethon from beginning to end. I wasn’t really alone I had my dog and pony.