Yeah but an undershirt is not quite the same as an email. For starters, undershirts existed alongside my Dad. Email accounts did not!
Your dad passed away before 1993?
Like you, my current email account is over 20 years old. I still have access to my 30 year old email account, too. I have my passwords written in a safe, next to my will, for my adult children to access after I pass away -- should there need to be anything looked at to close my estate.
So, minor children today could easily have access to their parents' 20+ year old email account... Particularly if they already have access to use their parents' credit cards for occasional online purchases.
Both credit card and email age lack as acceptable age verification online, in my opinion. just like an old t shirt, it has holes.