Exactly!

it's an 80s movie. they dont concern themselves with filling plotholes. but fun to watch!

I'm voting for legitimate transfer. The problem is the dates. I think this happened very late in the school year, because the deadlines for the articles (I just watched this again after about 15 years) were in May and Prom, which usually happens at the end of the year.

Terry was from a different school that was on spring break while she at the new school or she woulda known someone from the new school, which is why she chose a different school. So as to not blow her/ his cover.

Terry was actually at Sturgis Wilder for about two weeks. I assume that she faked illness for a couple of weeks, or maybe even managed a legitimate transfer, and transferred back when it was all over. I assume she forged the signatures with no one being the wiser since her parents were away.

This film requires a huge suspension of disbelief but it is well worth the effort.

I wondered the same thing. Nobody at her school noticed she was gone? How did she transfer back once her "experiment" was over?
I think she was at the school pretending to be a boy for about a week.