I work in Student Services at a college, mainly with freshmen, and often with students who are academically "at-risk." There have been a wide variety of responses here about what to do and I have seen all of them done successfully. Which one works for you will depend on you and your DD.
I would recommend that you talk to your DD and tell her what you have heard. As was mentioned previously, you may not get a mailed grade card - my school has grades online only and students have to log in to see them. This is not because we don't feel parents should be involved or because we are unconcerned about the fact that parents are spending a lot of $$ at our school but because the federal government requires us to keep academic information private and available only to the student. We could lose Federal Financial Aid if we are found in violation of FERPA.
We do STRONGLY encourage our students to keep their parents in the loop, but ultimately it is up to them whether they do so or not. We are not allowed to make that decision for them, no matter who is paying. A lot of parents expect us to mediate that conversation - I'm paying so I should have access to info. I don't disagree with that sentiment but that agreement HAS to be between the student and parent - I won't pay for your college unless you give me info.
So, if your DD really is failing two classes, you and she need to figure out what your best plan is.
A LOT of freshmen get off to a rough start, and usually not because they can't do the work but because they don't have good study or self management habits/skills. Many of these students do poorly their first semester and that is enough to make them realize they need to do something different. If your DD seems to be one of those students who is willing to make that change, then you might want to help her explore her options for the spring. She will most likely be placed on some kind of probation that will require her to use some academic services. If not or even if she is, help her find out what assistance is available and tell her that she needs to commit to using them. At my school we have a full time professional staff member who only works with freshmen who are struggling. She does tutoring and time management with them and many meet with her on a weekly basis. We also have peer tutors, writing staff, accommodations staff, etc... - basically a LOT of free help that is very underused.
I have seen MANY students who come back in the second semester WITH A PLAN FOR GETTING HELP that go on to do very well. The plan is the key.
On the other hand I also had one student who failed all of his classes because he would only go if his mom yelled at him to go.

She would literally call him before every class and see if he was going. He did not return after the first semester and I think that was for the best. I really think he was not ready to be out on his own.
So, give your DD a little push to get help - if that seems to motivate her then she is probably good to continue and will do well. If she seems to need a big push or ongoing intense pushing from you, then she would probably be better off staying home and working for a while or going to community college while living at home. Give her one semester to do better and tell her that her continuation next year will depend on how well she does in the spring. While I see many freshmen bounce back and do well, I rarely see students who do poorly two, three or more semesters in a row manage to pull it together.
Sorry this is so long - this is just an issue I am so passionate about. I see so many parents and students struggle with these issues and college does cost so much $$ that it is hard to feel like any of it is wasted. However, the lessons your DD can learn about herself and what she need to do to get what she wants out of life and what she can do to help herself can be really valuable too. Good luck to both of you!
Terri