I chose a bad topic and now I'm stuck. I'd like to delete the quiz and start again with a subject I have more knowledge. It's my first quiz, so I can't delete it.

There's no need to delete it.
Just delete the contents of the two questions you've written and you now have a blank template. You can then change it to the category of your choice and write the quiz questions.

Just remember if you've already worked with an editor to talk with them first!

I'm not sure if this is worthy of its own thread, so my apologies for piggybacking off of this. I submitted a question for the "question quest" and then realized that it might not be 100% clear, so I added a hint/example to the title and resubmitted it. (I figured that I'd try and save the editor's time)

Now I have 2 99% similar questions in the queue. I'm sure that it will be the same editor and that they will notice and take the "better one" (or reject them both if they are not good enough)

I just wanted to point attention to my mistake and I'm not trying to insult the editors by submitting the same question twice.

What category is it in?

Found them. Both of them are now back with the author.

I just see one of the two back. My apologies for the inconvenience. I'm pretty sure it was under "General"

Thank you for your help!!!