Question about AU and keeping a credit card with a low AAoA
I just got added to my father's credit card as an AU and wanted to ask, approximately what kind of increase in FICO score can I anticipate with this move? His AAoA is 10 years with no missed payments and 0% util every month, and my AAoA for all the credit cards is 3 years. I imagine this should help me a little I just wonder by how much.
I also have a question regarding one of my credit cards. The card is an Express credit card which I signed up for in 2010 but never use and all my other credit cards I got in 2007 and do use. From what I understand, the fact that the Express card is only 2 years old, it reduces my AAoA. So my question is, would it make sense to just close that account and if I did, would it increase my AAoA, therefore increase my FICO score?
Starting Score: EQ 606 TU 575 March 12th, 2012 Current Score: EX 639 EQ 618 TU 649 Goal Score: 720