Continuity mistake: When Donna sees Eric in the driveway, and they apologize to each other, her two braids have a mind of their own as they move up, down, and every which way, as she and Forman speak.
Continuity mistake: Aston Kutcher slides out behind the car and screams in excitement while blowing an air horn. When he does, the wind messes up the front of his hair. A few shots later, it's neatly combed again.






Chosen answer: He isn't. Time moves slowly in the show because they didn't want it to turn into "That '80's Show". In the first episode, he say's he's 17 but the second episode was his 17th birthday so he must have been 16. The first 12 episodes are set in 1976, the next 2 seasons are set in 1977, the next 3 seasons are set in 1978, and the remaining shows take place in 1979 with the final show on Dec 31, 1979 when Eric must be 20 as he turned 17 in 1976.
Myridon