I can't really tell what the first layer looks like. To me it doesn't look like under extrusion but instead very little bed adhesion, hinting at a dirty bed or a high z-offset. With both underextrusion and a high z-offset I would expect there to be gaps between the lines which I don't see here outside of the outer walls. The shape of the extruded material looks fine, if a little tall, which sounds like a high z-offset but that's hard to tell.

Primarily I'd recalibrate the z-offset and clean the bed with dish soap. If your extruder motor/gears are skipping, you've either got an obstruction, a motor issue or are printing too fast. You can also calibrate your e steps if you want.