This is about Jimmy getting sick of being a mod. He has to keep being mod to have friends and his life is getting torn apart. He is also arguing with himself whether or not to go to the beach fight.
Zoot Suit was the B-side of The Who's first single: I'm the Face. This single was recorded in 1964 when the Who were called the High Numbers. By adding this line, Pete was refering to the Who's mod days.
This is about Jimmy getting sick of being a mod. He has to keep being mod to have friends and his life is getting torn apart. He is also arguing with himself whether or not to go to the beach fight.