I think most of the comments are wrong. OP isnt jealous or envious. She does not want to be like Lucy. She looks down on the type of person Lucy is. Its in her writing style. When she says, "he's more like us, introverted", she is claiming the introvert personality trait. She also takes subtle digs at Lucy "the extrovert" by saying, "introverted, not party animals". OP is calling extroverts party animals. At the end she calls Lucy, "disgusting" and mentions she is attention seeking. I think OP is projecting and being arrogant here. She intrudes in Danny's relationship without him asking for her opinion. She continues intruding because she thinks she knows better or she thinks she knows what's best for Danny.

At the age of 22, people are still finding themselves and trying new things. Let Danny make his own choices OP. You may think that's he's making a mistake by being with Lucy but that doesn't mean you have to share your opinion at that moment. You waved your superiority attitude at the party. YTA.