When the show first aired the gang (Brandon, Brenda, Kelly, Steve, etc.) where Juniors in high school (I specifically remember reading this in the tv guide description of the piolet episode). The next season, which is another school year, they are all Juniors again. Did they all flunk their Junior year?
They were Juniors for a few episodes the first season. Specifically Season 1, Episode 12,One Man and a Baby. Brandon tells Melissa when he meets her by the tree that he is a Junior.