Translation of "Girlfriend's" in Chinese

I can't find my girlfriend's clitoris.

我找不到我女朋友的阴蒂。

My girlfriend's daughters have joined Facebook.

我女朋友的女儿是facebook的用户。

Before getting married, I called my girlfriend's mother "Auntie". After marriage, I started calling her "Mom" instead.

结婚前，我管女朋友的妈妈叫“阿姨”，结婚后，我就改叫“妈”了。