When all else fails, read the Instructions.

To Form 8863, page 7:

If any qualified education expenses for the student were paid
in 2024 for an academic period beginning in the first 3 months of
2025, treat that academic period as if it began in 2024. See
Student qualifications and Prepaid Expenses, earlier.

And Page 4:

Prepaid Expenses
Qualified education expenses paid in 2024 for an academic
period that begins in the first 3 months of 2025 can be used in
figuring an education credit for 2024 only. For example, if you pay
$2,000 in December 2024 for qualified tuition for the 2025 winter
quarter that begins in January 2025, you can use that $2,000 in
figuring an education credit for 2024 only (if you meet all the
other requirements).