Line Graph Over Time: When the Column Header Contains the Year, and the cells contain values.

silasmiddleton , Unpivot this data. You should get semester as one column

Unpivot Data(Power Query): https://youtu.be/2HjkBtxSM0g

Create a new table for the semester, example in Dax

semester = distinct(Table[semester])

Create rank on semester as a new column in the semester table

semester rank = rankx( semester , semester [semester],,asc,dense)

then create measure like

This semester= CALCULATE(sum('Table'[Score]), FILTER(ALL('semester'),'Date'[semester Rank]=max('Date'[semester Rank])))
Last semester= CALCULATE(sum('Table'[Score]), FILTER(ALL('semester'),'Date'[semester Rank]=max('Date'[semester  Rank])-1))

Same logic as week or custom period

Time Intelligence, DATESMTD, DATESQTD, DATESYTD, Week On Week, Week Till Date, Custom Period on Period,
Custom Period till date: https://youtu.be/aU2aKbnHuWs&t=145s

Join with semester of table