Currently I am 23 years old and I got my first Credit Card at age 18 through a joint account with my father. It's a US Bank Platinum and at the time also got a 19,500 dollar car loan through them (never missed or had a late payment on either and the car loan is payed off). I was thinking of closing my Platinum joint account since I don't want to have a joint account with my father anymore. I currently have a 730 CS and have other credit cards listed below:
-Best buy CC
-US Bank Premier line
-Amex Premier Gold
-US Bank Platinum (same as joint but this one is on my own)
So my question is how can I find out how closing US Bank Platinum CC joint account (being the eldest account) will affect my Credit Score being that it was my first card and have the longest history?