When I upload to Cricut Design Space, my circle is missing.

Circles that have been resized vertically or horizontally to look like ovals may not upload properly into Cricut Design Space. If you notice this, return to your illustration software and replace your circles (or remove them altogether).

If you don't want to remove your circles, here's another option:

1. Select all of the objects in your design in your illustration software (Edit > Select All)

2. Go to Path > Combine (in Inkscape) or Object > Compound Path > Make (Illustrator). 

3. Save and upload again.

Note: I have not taught you how to use these tools yet, but this is a solution to fixing the issue so you can move on.