One of my children took a class for credit during the summer some years back in middle school and I think it was self-paced and module based. Foreign languages may be structured differently.
If you or your student have not yet done so, I would visit the TTU link and dig around there as that would have the most current information (unless you are specifically looking for anecdotal info).
The link is here:
http://www.depts.ttu.edu/k12/and if you click on the individual courses link, can then explore from there.
If you have not yet done so, I would encourage your student to do this, either alone or with your guidance, and also to make a list of her/your questions and submit them using their online form. (the 'contact us' link at the top of their page). This is very good practice for a high school student to learn how to frame constructive questions via email in an academic setting that is not with their own teacher back home (who is familiar to them). A skill that will follow them through higher education and beyond. In other words, as the adult, teach your daughter how to ask the questions to find the information she needs to know in order to make the decision (whether to enroll) and reach her goal. If she already knows how to do this, sorry for sounding preachy--but you would be amazed at the number of adults out there who have difficulty with correspondence in academic and business settings and having a caring mentor who can guide them in this endeavor is a blessing.
Good luck to your student and great that she wants to continue learning.