eagerness
Strong, excited desire to do something right away.
Eagerness is the feeling of excited anticipation and readiness to do something. When you wake up eager on the first day of summer vacation, you're thrilled about it and can't wait to begin. That energy and enthusiasm you feel is eagerness.
You can see eagerness in how people act. An eager student shoots their hand up quickly and leans forward in their seat. An eager puppy bounds over to its food bowl with its whole body wiggling. Eagerness shows itself in quick movements, bright eyes, and an almost impatient energy to get started.
You're not vaguely interested; you're intensely ready. Someone might be eager to learn, eager to help, or eager to try something new.
Eagerness differs from simple willingness. If your teacher asks for a volunteer and you think “I guess I could do it,” that's willingness. If you immediately think “Pick me! Pick me!” that's eagerness. Eagerness is willingness plus genuine excitement and energy.