Everyone trying to defend the mom here is honestly...
Okay so, I understand and validate that the mom is mad and frustrated that her daughter and lied and didn't do trust her.
But what reason did the mom give to trust her at all?
She forced her daughter to stay in the closet for years, gave her no support despite expecting her to be top of her class, constantly fought with their partner in a place where their child could hear, and each time that the mother did find out about them dating, their only solice and happiness since the beginning of the story when the parents were yelling and she snuck out in the middle of the night to be together, her mother calls homosexuality a disease and demands they never see each other again or threatens to send her away.
This is classic abusive relationships 101.