MacBook Air 13" Early 2015 states service battery.

Check battery health says:

• Service Recommended: The battery's ability to hold charge is less than when it was new or it isn't functioning normally. You can safely continue to use your Mac but you should take it to an Apple Store or Apple-authorized service provider to get your battery evaluated.

To get service on your battery, contact Apple.

So yes, get it serviced.

yes, that's exactly what it means. aside from eventually not charging anymore, an older battery could start swelling up. at best, this can cause pressure on the trackpad causing undesired behaviour. and at worst can cause physical damage to the MacBook's hardware. and if it actually bursts, all bets are off. the contents of the battery are very corrosive.