Does the eternal now doctrine (2 Peter 3:8) teach that God doesn't know the difference in age between?

Between a Model-T and a Honda Odyssey

He knows all

If you are infinite, what is 60 years?

Absolutely not.

GOD is outside of the realm of time.

A word to the wise, check out the context verses… 2 Peter 3:

"3 Above all, you must understand that in the last days(E) scoffers will come, scoffing and following their own evil desires.(F) 4 They will say, "Where is this 'coming' he promised?(G) Ever since our ancestors died, everything goes on as it has since the beginning of creation."…

8 But do not forget this one thing, dear friends: With the Lord a day is like a thousand years, and a thousand years are like a day.(O) 9 The Lord is not slow in keeping his promise,(P) as some understand slowness. Instead he is patient(Q) with you, not wanting anyone to perish, but everyone to come to repentance.(R)

10 But the day of the Lord will come like a thief."

Suddenly, without warning…

That verse does not teach an "eternal now." It merely indicates that the passage of time has no effect on God.