All the gospel authors agree that a group of women (who love Jesus enough to attend to his body) went to the tomb and were the first to discover it.
This is recorded in a culture that valued women so little that their testimony was not even permissible in court. An invented story would not have included women as the first witnesses to Jesus resurrection. So, the agreement that it was a group of women makes the story all the more credible.
Scholars believe there were likely five women near the tomb. Apparently, all the writers knew of the two Marys but were less focused on the other women.