I moved to Mac full-time - having been a Microsoft guy - back with the purchase of my 2011 Air. A bit of a learning curve - still new discoveries as I go along - but it's still going strong. Glad you're having a blast with your purchase.
Though I never used it, I too would tell you to get AppleCare if you can swing it. No HDD to worry about, but 'stuff happens'.
Diehard Macolytes continue to insist that the OS doesn't need a virus scanner, but as the Mac has grown in popularity / market share, its also grown in attention from those who intend to do harm. And Apple hasn't always been the fastest off the mark in acknowledging / then fixing problems that users report.
Anyhoo, I use a virus scanner as a belt-and-suspenders move - and as I use a free one, it costs me nothing (and this one has very little drag on resources), so what's the downside?
I use Avira Free Antivirus for Mac - its not available thru the Mac Store, but a Google will find it. Fairly full-featured and it allows you set update / scan schedule and is 'always on'.
Avira is well-respected and reviewed - independent organization AV-Comparatives rates it pretty highly (
https://www.av-comparatives.org/mac-security-reviews/) and I've never had a problem.
Your Air's default Security setting may not initially let you install an application from outside the Mac store, but that can easily be tweaked to allow for this. Come back here if you need guidance on that.
Enjoy your new Air - glad you got in the door (and on sale!) before Apple kills off its most affordable and useful Mac.