>I speak english poorly and I would prefer to not compromise myself.
Your English may be pathetic or lousy or simply bad... Don't speak English poorly. Speak poor/broken English instead.
"Compromise" is not the right word.
You don't want to come across like a {...} who {doesn't know...} {fill in whatever you don't want her to think of you: clown? boob? the possibilities are endless, but try not to overdo it.}
She'll swallow whole anything you say along those lines. But don't you ever go over the top with this voluntary self-humiliation business. It may and will backfire when you least expect it.