aphony-cree:

Dean was constantly moved from school to school and since there were no nation-wide standards for curriculum he would have been consistently thrown into different lesson plans. He would have left one school where they had just started learning about World War 1 to discover that at his next school they were almost done with World War 2. He would have been expected to catch up on his own (because we all know John didn’t devote time to helping him) and hand in assignments along with the rest of the class where he would have been graded the same as the students who got full instruction on the subject even though he’d missed most of it.

Dean’s first priority was taking care of Sam, which would have included helping with his homework. Ever wonder how a kid who got moved from school to school so frequently earned a full ride to Stanford? Ever consider that part of Sam’s success is probably owed to Dean helping him catch up on missed lessons because he knew how important school was to Sam? It’s also owed to Dean taking care of every parental responsibility so that Sam could be a normal kid who’s main priority was homework.

In My Time of Dying 2.01 John talks about all the times he came back from a hunt completely wrecked and Dean had to take care of him. When Dean wasn’t being a parent to Sam he was being a parent to his own damn father. On top of that he was expected to study weapons and lore so he could protect his brother, which was drilled into him as his number one priority since the age of 4. So let’s look at what would have been an average day in the life of young Dean Winchester:

He gets up, makes breakfast, gets Sammy up, gets them both to school, spends about 7 hours there, goes back to the motel, does a weapons check and makes sure the room is secure, helps Sam with his studies, makes dinner, does the weapons/lore work that John would have ordered him to complete, puts Sam to bed, by then John’s probably back and Dean has to take care of an emotionally wrecked (and probably drunk) grown man which may last until Dean’s bedtime or may last well past Dean’s bedtime depending on how bad John’s day was. Not only would Dean have had little to no time for his own school work but he would have often gone to school on not enough sleep thanks to all the responsibilities he had at home.

But you’re right, Dean being held back must mean he’s not smart. If he were truly intelligent he would have magically known all the test answers without studying and been able to do his homework with one hand while the other one packed salt rounds and made dinner. 

(Sorry for the sarcasm, I know it’s rude and I usually don’t get this way but this question really got to me. School success is not always a reflection of intelligence, it’s often a reflection of how you were raised)