Age of my iPad

Seems that is a 1st generation iPad Air. They were released in 2013 & 2014. Your warranty is expired, and the device will not run an iOS higher than 12.5.5. Can't be exactly sure about what date it was manufactured, but within a couple of years, depending on when they stopped selling that device, but the second generation iPad Air that replaced it was released in 2014.

Not possible to know from serial number. Also, it's not a good idea to post your serial number in a public forum.

You can identify when it was first released, but for specific age of your device, only the purchase date on your receipt can be used.

With that said, that is a first generation iPad Air first released in 2013.