This is what you found!
ANSWER YES.
If you paid for classes in 2020 that started in 2021 (and I assume you did or you wouldn't be asking this) answer Yes, that you were a student in 2020.
Additionally, the 1098-T might report that you were less than half-time if you didn't attend in 2020, but that is not true for taxes.
According to the IRS:
“For 2020, treat an academic period beginning in the first 3 months of 2021 as if it began in 2020 if qualified education expenses for the student were paid in 2020 for that academic period.”
So Yes, you were a student in 2020 and yes "at least half time"
