The only answer I got from my mother was that this world is dominated by Satan and thus we cannot trust in worldly chronologies.
You'll not shake the faith of a true believer. Doesn't matter whether they are JWs, exJWs or any other believer. Yes, there are even exJWs who still believe in that nonsense about God creating Adam and causing a flood. It didn't happen, but don't bother getting bogged down trying to convince someone who will not listen. All the facts and evidence in the world will not convince them otherwise.
For your own benefit, though, try Googling your questions but stay away from the creationists websites. They are complete nonsense as you'll find out by seeking true answers to your questions.
Here is an example of what you can find: