Very new to blender, fill issue


I’m running through the blender bootcamp from blender tutor. I was creating the cup and extruding the base with edges selected. When I hit f to fill it only fills a semi circle of the base even though all edges are selected. Can anyone tell me why? This is right after extrude so all edges are active. The current fix I have is to merge to centre but I still would like to know why the fill wouldn’t work. I did the internals of the cup following this and the fill worked fine for the internal base.



which tutorial on the site was it? (link please)

you might have forgotten to remove doubles

in edit mode, select all vertices and click on the button in the left panel that says “Remove Doubles” and try again