What should I know before going into organic chemistry?

Organic chemistry is very different from general chemistry. Whereas general chemistry focused more on the mathematics applied to doing labs and some major conceptual knowledge, organic chemistry focuses more on the geometry of organic molecules and how their shapes, figures, bonding, etc. promote such diversity that we see today. So your best bet would be to refresh your understanding of the VSEPR theory, basic structures such as tetrahedral, square pyramidal, orctahedral, etc, along with basic organic chemistry groups such as carbonyl, carboxyl, amino, etc.