Datte Suki Nan Damon
From Bad Eggs:
Moka's brother Megu is returning from New York City where he lived with their father. Not only that but she saw a tv program on art and is now interested in the subject. When she goes to the library she meets Masato-kun who she begins to like. But Masato-kun turns out to be a playboy. What will happen to Moka's first love?
Serialized in Ribon from 11/2004 to 8/2005, compiled into two tankoubon