Your chainring isn't worn at all beyond some normal chain scuffing here and there. What you're looking at is the shifting gate that's cut into chainrings (the glide in xxxxx-glide) to improve shift response. These are only cut into larger chainrings, including the middle of triples to help the chain climb up, or drop off. You don't see them on the smallest ring because the chain lifts vertically off them rather than derailing to the side in a shift.

Teeth near the gate also see some increased wear because they're struck by the plates as the chain shifts on and off the chainring. Teeth elsewhere do better because they're always meshing perfectly with an already engaged chain.

This question is so commonly asked that there should be a sticky showing a blow up of a typical shift gate, with an explanation.