Mrs. Kersch: You know what they say about Derry. No one who dies here ever really dies.
Mrs. Kersch: I was always daddy's little girl. What about you? Are you still his little girl Beverly? ARE you?
Pennywise: Hello.
Richie Tozier: This meeting of the Losers Club has officially begun.
Answer: Pennywise eats Adrian Mellon because he has just awoken from his sleep and is hungry. Pennywise will feed on anyone but prefers his victims to be afraid because the meal is more satisfying. It is described in the book as like "salting the meat." Likewise, Pennywise prefers children because their fear is more intense.
BaconIsMyBFF