It can seem as if she is being very accommodating and that you are being quite understanding right now but please realize that you two are still dating and exploring each other right now. You are both putting on your best faces, you stating that she is still a good person with very good morals and her agreeing to attend services with you. Later on, if she refuses to attend services you will feel that it was all an act. And if you insist on pushing the issue, she will feel coerced. If she was raised Mormon and that resulted in her being agnostic, then you will need to address that.
Children are an abstract idea to you both right , thinking about what you’d like. Once your child or children are born, the instincts become almost visceral. You will want your children brought up in the Catholic Faith, you’ll want them to experience the fullness of the faith with baptism, first communion, confirmation and all of these require responsibility. Its really hard to imagine anything different if you are Catholic. But try to imagine your faith and raising your children in the faith with someone who is not fully engaged (or involved). Its hard. And when your children have questions, how will that be handled?
I think you should pray long and hard before becoming involved with someone outside of the faith, especially someone whose family is a completely different faith and ended up being agnostic.
Your future and your children’s future depend on you!