Hi @Annette Evans Wilson
Welcome to the LastPass Community.
I'm afraid the way Google works is, when you log into one section with your account credentials (such as Gmail), you also have access to the Calendar, YouTube, Docs and other related work areas. You can however, create a shared Doc / Sheet / Drive and grant your assistant permission to access those.
This is on a desktop browser, but on the lower left is a list of your calendars. Click the three dots to the right of the calendar you want to share, and select settings and sharing. In that settings window you can then assign the calendar to other people.