Something to ponder. Could Christ have done it without her? In a certain sense no. He needed Mary to be truly made man. A theophany would not have sufficed for true God to be made true man.
And in another larger sense, yes.
Unless, of course, you believe that this was simply beyond what He is capable of.
The Virgin Birth was foretold and was a sign and wonder that heralded His arrival.
But if it was not to be, the prophets would have foretold a different prophecy and we would have still beheld a sign and wonder that heralded His arrival.
Still, not recognizing Mary as Christ's first and greatest Saint is not a wise path.