extruder nozel scraping last layer

I am new to 3d printing. I assembled a Reprap Prusa i3 DIY 3D Printer. Bed is level and a piece of paper slides under the nozzle with little resistance.

Seems like the first layer prints good. Then after it looks like the nozzle is scraping the last layer.
Looks like the nozzle is plowing the pla around and causing bumps and scrapes. it gets worse every layer.
Also it seems like if I do not load the object into cura first it seems to print much better. This is driving me nuts. Hope you guys can get me going in the right direction.

If your first layer is good, but the second layer is dragging the nozzle around, it sounds like your Z calibration or Z steps are too low and when it moves up by the layer height it doesn't move up high enough. Alternatively, if your Z is calibrated properly, is your nozzle attachment loose? Perhaps after the first layer it hangs down or wobbles and is not securely fixed without any play?

The nozzle is solid and is not moving around.
I am using cura. How do I calibrate the z axis? Do I set it in cura under expert settings in "Z distance" ? It is set for .15?

you have to check your step/mm for Z.

Home and mark the position ask 100mm and mark the position and then measure it should give you 100mm when you ask 100mm if its not you have to alter your step/mm (M92)

here the formula in case your not having 100mm

new_steps = old_steps * (100 / distance_actually_moved)

looks to be exactly 100mm. Not sure what else i can do.

Maybe you're over-extruding, so that if the layer height is (say) 0.2mm, the plastic actually comes out 0.22mm thick.

Check you extruder calibration... mark the filament with a Sharpie at some distance (say 20mm) from the extruder, measure 100mm from that point and mark again. Command a 100mm extrude, then measure the distance of the second mark from the extruder and subtract the initial 20mm.