Bare in mind that if we're going by the continuity of Bewitched, then Tabitha Stephens was born in 1966 (https://bewitched.fandom.com/wiki/Tabitha_Stephens). And while we're at it, how did Adam, who was born in 1969 (https://bewitched.fandom.com/wiki/Adam_Stephens), suddenly become Tabitha's older brother?