Last year I put my GF on 4 of my Amex accounts. I notice this lowered her AAOA from 7yrs to 5.2. If i remove her from the accounts and they report closed. Will this bring back up her AAOA. Thanks
Any new TLs will lower the AAoA whether it is AU or the primary holder of that card. The only way you could get away with not having an AU card affect your AAoA would be if the lender could not match you with your CR.
For example, if the AU does not share the same address or contact info and the lender did not request a full SSN. You would still get the card, but it would not be reported on your CR.