Legal Question in Immigration Law in California

A U.S. legal permanent resident who plans on being outside the U.S. for over 6 months needs a re-entry permit.

At this point, upon her re-entry into the U.S., you can have her bring evidence of why she had to be outside the U.S. for so long, as well as proof as to her intent to remain in the U.S. permanently, despite her long stay outside the country without the proper re-entry permit.

Since she is a minor, Customs & Border Protection might go easy on her, however, I highly advise that she re-enter with an adult who is a LPR or U.S. citizen, who can help her through what could be a difficult process at the U.S. port of entry. Of course, there is no guarantee that they will re-admit her, however, with the right documentation, she should be able to get back in.