Why does my student's profile say "Enrolled before"?

Because this student was imported without an enrollment date (column missing or empty, or import by photo). The app kept the import date and marked it "estimated". The profile shows "Enrolled before {date}" to make this visible: the real date is earlier than the one shown.

For the Martialnote plan, a record imported without a date counts as active only through its activities in the last 90 days (attendance, dues payment, curriculum item learned or validated), never through its enrollment date. The owner can correct the date (Edit > Enrolled since): the note disappears, but this changes nothing in the number of active students.