22 is a very young and vulnerable age. College graduates, yes, seem intelligent but are still trying to figure life out and during that period, they can be victims to a lot of people, economically to emotionally.
I understand you feel the need to take the 300 dollars for your child but I wonder what really motivated you to ask her to pay rent and ask her to eventually leave. You have options of letting her put it in a savings account or you place it in a savings account for her that she could touch later in life or you could have asked for something very different all together.
She went to school with dreams and goals, she was unable to meet them to her standard, she returns home to find her parents acting distant and more business orientated. It seems like she was more interested in some form of emotional support or the very least a therapist about this new chapter in this young persons life.
You can do whatever you want but understand that actions have consequences and she is still significantly younger and still needs guidance. You communicated very clearly that you are unwilling to provide that to her.
I would never think to do this to my children. It would never cross my mind to physically or emotionally abandon my children, especially over some rent money and a few dishes in the sink.
Be honest, you didn't want her in the home for personal reasons you will not admit to anyone or even yourself. Take a look inside and reflect on your actions. She is still incredibly young and learning.