Hey OP. The single thing that would benefit you most at this point is learning the difference between reports and scores. You need to understand who the "big three" bureaus are, what it means that they have a report on you, how to read that report, and what tools will give you the ability to get free and frequent updates to these reports.
You write: "Yet according to FICO my oldest account which would be a credit card from that bank is 11 years old...."
That's an example of why you need to understand the basics here. FICO is a company that makes credit scores. It has nothing to do with managing and maintaining the actual data that are on your report. The three groups that do that are Experian (EX), Equifax (EQ) and TransUnion (TU).
Likewise you write: "I'm just wondering how badly my score will drop if this card ever falls off my credit report since it did on CK which is irrelevant....."
If this account was showing on CK and does not now that is in fact very relevant. That's because CK shows you all the data from two of the three bureaus: EQ and TU. Again, what is relevant is what was in your reports and what is showing now.
You can get free and frequent TU and EQ reports at Credit Karma. You can get a free monthly EX report at creditscore.com (plus a free FICO 8 score with it).
BBS and I encourage you to look closely at your actual three reports (ignoring scores) and then tell us what you see. Does the account appear on it? If not, do you have an older report to compare it to where it did? Was it listed as Open or Closed? If closed, what was the "Date Closed"? Etc.
