Selecting the edges of a circle but it doesn't select the face? (Beginner)

Hello, I am building a mug and when trying to inset the top circle of the cylinder I press alt and click to select the whole ring.
However it doesn’t select the face of the circle, it just selects the ring.
I know I can just switch to face select mode, still I wonder how else I can do it since the guy in the tutorial also uses the point selection mode. this is the tutorial, it happens at around 20:01

EDIT: I figured it out, apparently when pressing alt and clicking at a point on the desired ring the cursor has to be very near the ring but also on the face.

EDIT 2: tried to do it on the bottom side but it doesn’t work, please help me!

EDIT3: apparently you have to enter the sceleton mode if you try it from underneath, I whonder why

Happy Blending everyone!

He’s in vertex select mode.
Make sure you don’t have any overlapping vertices/doubles.

Post your .blend.