"Did you know" vs. "Do you know" I have a special talent?

I realize this question has been addressed before, multiple times, and I’m aware of the "rules." However, I’m less concerned in this instance with being right than with sounding natural — i.e., pleasing to the most people, especially elementary-school children and their parents and teachers, since the sentence in question is for a children’s book.

Thus, in the manner of a poll, I would be grateful to hear responses regarding what you would use. Here is the sentence:

Did/do you know I have a special talent?

This is the first line of the book and hence particularly important.

Which would you use: "Did" or "Do"?

Many thanks!