Is it normal i didn't know?

I'm the single dad to three girls, age 8, 5 and 2. A neighbor had to go out and asked my oldest to baby sit her 1.5 year boy, which was pretty silly. An 8 year old responsible for a child's life and care? Nope, of course it fell on me to oversee. Longer story shorter my child had more pressing problems (in her mind) than changing the baby boy.
Well come on people how was I to know? I've changed thousands of diapers on my girls; no problem.
Little girls leak, little boys SHOOT. Right into my face! Yuck.
Now we both need a cleaning.
How was I supposed to know?