Right, so keeping a card just because it is the oldest isn't really needed either.
AAoA in FICO (though not in Credit Karma) is based on open AND closed accounts that are on your report. Closed accounts generally cease to report after 10 years (although it can be sooner) so you lose nothing for those 10 years. And by then, hopefully, your credit situation is different (and better).
So with your US Bank CLI, are you going to ask to PC to Cash Plus?