Reading Journal

"Then Cassidy scampered down the ladder of the tree house and dashed off into the night in hopes that she'd enjoy her last few hours of summer freedom, even though she was worried that it wouldn't get much better than this."

I've just started The Secrets of Boys and the main character, Cassidy is a quiet, but passionate person. This quote raises a lot of confusion for me because she is leaving her old friend's house and is on her way to see her boyfriends, but she doesn't seem that excited. So, my main question is why isn't she happy to go see her boyfriend?