Love / Asking Polish parents for permission to propose to my Polish girlfriend - help [5]

Hi everyone,
I'm planning to propose to my (Polish) girlfriend, we've both discussed it and know it's what we want to do.
I've met her father quite a few times, as well as the rest of her family. I want to ask him for his permission on our next trip there soon.

I still want to keep it a surprise for her so he needs to know to try and keep it a secret. My Polish pronunciation is fine, I can speak some broken Polish but really need help to get this right.

Below is the English version and the rough translated Polish version (probably very wrong).

If you could help me translate, so I can practice, maybe even suggest a way of saying it that would seem more natural to her father (rather than the English way) I would be forever grateful.

English version:
I have a question to ask you. We do not know how to speak each other's language, but I have learnt to say this because it is very important to me.

I am seeking your permission to ask your daughter to marry me?

*Hopefully an answer here*

Please keep this a secret until I have asked.

Polish version:
Mam pytanie zadać. Nie wiemy, jak się mówić nawzajem język, ale nauczyłem się mówić o tym, ponieważ jest to dla mnie bardzo ważne.

Szukam Twojej zgody, aby zapytać córkę o rękę?

*Hopefully an answer here*

Proszę zachować to w tajemnicy, dopóki nie zapytałem.

Dziekuje!