How to debunk the first cause argument without trying too hard

[robvalue]

You set up a rule, that everything has to have a cause, has to have something before it, or whatever.

Then you go and break your own rule by saying "Actually there is one thing the rule doesn't apply to."

You don't give adequate justification for why it breaks the rule, it just does because you say so. So the rule isn't a rule, after all.

Most importantly, you don't say how you can possibly know the thing you describe can exist. Feel free to take it to any logician you like, you'll get told the same. Don't take our word for it.