is AAoA only for credit card accounts or if i apply for a loan, that is also considered as an account in the AAoA ?
Installment and mortage loans will factor into your AAOA.
To add, AAoA is the average age of all of your OC accounts, whether opened or closed, good or bad. So it includes CCs and loans as mentioned, but also includes accounts like HELOCs, LOCs, and even charge-offs. AAoA does not include CAs or PRs.