May-gin works, too. Depends on the Megan, much like it depends on the Sara or the Nicola.
Here in 'MURICA, the first syllable is either may- or mə- and the last syllable is either -gin or -gən, sometimes even a full -gun if you're in Mississippi or Tennessee or some other place with a weird strong dialect. Mee-gin just sounds... wrong. Very wrong.