Chosen Solution
Double check if you didn’t wait before you took the snapshot, as its reporting opposing info! The Power Adapter is Connected the batteries health appears to be OK, but the Full Charge Capacity is clearly not full! And the system is Discharging the battery were it should be Charging it! Turn the system off and leave it under charge for the night (good 10 hours) and recheck things in the morning. Take a fresh snapshot and post it so we can see where things are. Update (12/30/2021) @daace - Check the MagSafe cable and the connection. Does the cord look like these?
If they do you need a new MagSafe charger Apple 45W MagSafe 2 Power Adapter for MacBook Air Don’t go cheap! The knockoff chargers can damage your system and some have stated fires! Don’t Replace Your MacBook Charger With a Cheap KnockoffOEM MagSafe Chargers vs Cheap Imposters: Teardown for TruthLacking safety features, cheap MacBook chargers create big sparksFAKE Magsafe MacBook Chargers on eBay - Watch before buying a Mac Charger Inspect the MagSafe contacts! Are they discolored or burn’t? You may need a new MacBook Air 13" (Mid 2012) I/O Board
Is the grey insulator area dirty?
Use some 90% or better isopropyl alcohol with a cotton swab (Q-Tip) to clean the area and use a fresh pink pencil eraser to polish the contacts.
