The adjective ignorant, which means “lacking knowledge or information,” is often used with the prepositions of and about, as shown in the three examples below. In each of these sentences, either ignorant of or ignorant about can be used:
On the other hand, ignorant to is rarely used, and in your example sentence:
ignorant of sounds very natural, while ignorant to sounds awkward and wrong.
Therefore in general, I would recommend using of or about, rather than to.
I hope this helps.