My mom was the unplanned twin. My grandparents had two girls and wanted a boy. They tried for a boy, got a boy, but also got a bonus girl (my mom).
I have a triangle shaped bag that hangs off the frame of the bike between the seat and the handle bars. I just cram my baseball cap in there. Don't take a nice one you don't want to crumple up a bit though.
Well, she's probably seen more of them than you.