ipad air about four years old

If the device is shutting down despite displaying 100% battery and attempts to reboot are not working, then yes, I would suggest that you make an appointment at the Genius Bar of the nearest Apple Store or Authorized Apple Service provider.

Not a lot of information with your post to offer any potential solutions. At this point, based on what you have provided, I would suggest that you make an appointment at your local Apple Store or Apple Authorized Service Provider to have them take a look and provide you with your options.

However, before you go, you can try restoring your iPad. To restore your iPad, connect it to your computer. When the iPad

appears in the iTunes source list, click the Restore button on the Summary tab. (Note: A Restore will erase all of your data and media and resets all of the iPad's settings. You will need to restore your data from a previous backup from either Finder/iTunes or iCloud.)