I remember trying to work out the date of the flood using the bible stories book when I was about 7 or 8; we were studying ancient Egypt at school at the time. I was very confused because my date for the flood was around 2250BCE* but at school we'd learnt that the Egyptian civilisation began more than 5000 years ago, which contradicts the JW belief that the Egyptian civilisation descended from Ham, after the flood. Even the pyramids & sphinx at Giza pre-date the flood by a couple of centuries.
I could never reconcile this in my head, and I never received a satisfactory answer about it from my parents, who from what I can tell simply ignore inconvenient facts like that, with surprising ease.
*I know that the actual date that JWs use is around 2370BCE, but I had limited information available to me in the bible stories book, and this was before we had the internet. It's academic however since the Egyptian civilisation still pre-dates the flood by several centuries.