You need to talk to a member of your bishopric/clerk/executive secretary. They're responsible to managing the rights to the calendar. Just because there's a calendar with the words "Young Women" in the title, doesn't mean the YW president has rights to add things to that. Editing privileges are separate from the text in the title.
Also, if you've just been called to the position, it can take up to 24 hours after the calling is recorded for your rights to take effect.
Have you searched the
Help Center? Try doing a Google search and adding "site:churchofjesuschrist.org/help" to the search criteria.
So we can better help you, please edit your
Profile to include your general location.