I got 3 credit cards within a short period of time (2 months, maybe) and got penalized for it. If I close one of those cards, will it helps by adding back to my AoA, since every card shortens it? I hope I'm not clear as mud here
No. Closed accounts count the same toward AAoA under FICO scoring as open accounts do. If you closed them now, they will continue to impact your AAoA for 10 more years until they fall off.
You won't gain anything AAoA wise from closing them, so since you've already taken the inquiry hit opening them you may as well keep them open.
Bummer now maybe, but think on the flipside that 10 years from now and longer (if you keep them open) you'll have that many more old accounts factoring into your AAoA, strengthening it.
You can contact the creditor and make a request that they delete all reporting, which will remove the account from your AAoA calculation.....
That's a very good point above, I hadn't actually thought about that option and it's certainly a smart one for anyone that opens an account and decides to quickly close it for whatever reason.