Your daughter may be 19 but is she entirely independent? Does she, as do most young adults just out of high school, depend on you for a home or for other financial support (e.g., education, health insurance)? If she is entirely independent, you are limited to prayer, sacrifice, and talking to her about religious issues when opportunities arise. If she is in any way dependent upon you, you can explain to her that, while she may be a legal adult, her dependence means that she is still subject to your authority.
If that is the case, you could tell her that attendance at Mass is a family responsibility and you expect her to go, even though she should not receive Communion right now. If she refuses, then draw up an “exit plan” to transition her as quickly as possible away from being financially supported by you. If she agrees to accept your authority as a condition of accepting your financial support, you should assure her that you will not force her to talk to a priest or go to religious education classes (as you would do if she were a minor instead of a legal adult). You may though point out to her that doing so on her own could make going to Mass easier to deal with because she will have a forum for asking her questions and expressing her concerns about religion.
