No problem,
I suggest creating a table of School Terms. That table will hold your drop down choices for the School Terms. If this is a new app with no data yet, then I suggest leaving the Key field of that table being the Record ID. If you have a lot of data, too much to Grid edit then post back and we can deal with that.
The fields on the table will be
Term Name (text field)
Start date (date field)
and the rest of the fields will be formula date fields.
The formula to adjust a date to a different month is
AdjustMonth([Start Date], -1)
for example that would make a date calculate to 1 month before the start date.
Then you will make a relationship where 1 School Term has many Courses, and then lookup all those data fields down into your Courses record.
Post back if you have any questions.