There are probably close to a half dozen threads here in this forum that discuss one form or another of managing class attendance. You may want to enter "attendance" in the search the forum box at the top of this screen to see how others have approached this issue.
Any such system starts with setting up tables and relationships to support tracking attendance. You might have the following tables in your database arranged in relationships similar to:
This uses 4 data source tables:
Students: One record for every student
Enrollment: One Record for each student for each class they are taking
Classes: One Record for each different class you offer to your students (Each "class could be a different martial art, different age/skill level or combination of all of these.)
Attendance: One Record for each class session for each student.
EnrStudents and AttStudents are two table occurrences for the same Students data source table. In like manner, EnrClasses and AttClasses are two occurrences of the Classes data source table. This is not the only way to set up manage | database | relationships to do this, but keeps your enrollment and attendance tasks as separate parts of the same database, even though they use the same class and student data.
How close does this come to what you have?