Prove that you exist

Absolutely.
Little bit of knowledge of how genes work and little bit of common sense dictates that you are unique continuation of your genetic line which assures its survival through time.

caught me off guard

I'm rubber you're glue, whatever you say bounces off me and sticks on you

There is, therefore there must be at least me.

It's okay Descartes, you still did chill math stuff.

I can prove it to myself, but not to you

Left as an exercise.

why would I need to prove that?

Prove that I don't faggot.

no u