Yeah, so there will be a bit of a short-term hit to the FICO for closing the older card. It's how th FICO math works. If neither card have fees, and to answer your first question -- yep, you'll see an effect. If you don't need to close the account (no fees, right?), can you just park the card you thought about closing in a firesafe, and only use it for a tank of gas every four months or so? This keeps the card 'active' so the bank doesn't unilaterally close the acct for non-use. Yes, that's a thing.

Sorry -- I'd usually tell you to kill every account you don't need. But in this case, you'll have a hit that will last a few months to a year or more on the FICO.

Oh, and while we are on the topic, at least once a year pull your credit report and review it:

Use www.annualcreditreport.com to review all credit accounts, freeze all credit reports with Equifax, Experian, Transunion (use their free services)

Search for how FICOs are calculated -- there are 5 components to it, with account longevity being a fraction. On-time payments are the way to really build a great score as the years go by. Never carry a balance on non-mortgage accounts -- debt interest slavery is bad for your wealth.