OPTION A:
Log your phone into your iCloud account.
Log her phone into her own iCloud account.
Then turn OFF her calendars in her iCloud settings.
Then, on her phone, go into her 'Mail' settings and set up a new Mail account using YOUR iCloud info. In that, turn Calendars on and everything else OFF.
or
OPTION B:
(IF you want to also share Photostream and Pages documents then flip it around on her phone...make your iCloud her main account on her phone and HER iCloud as her secondary iCloud account. Then turn various things on or off depending on if you want to share them or not share them.)