Wikipedia says UCLA. And it looks like they went to a public high school in Illinois - Neuqua Valley High School.
More specifically it states that she first attended Glendale Community College to study acting before attending UCLA. Neither of these are online programs, although there were possibly online classes offed at the community college. Although it is hard to take acting classes online.
Because of the strict child labor laws in CA, even if she graduated H.S. she would have been required to attend school of some sort till she was 16 even had already graduated from H.S.
