Alice in April / Phyllis Reynolds Naylor.

Enhanced descriptions from Syndetics:

April is the cruelest month," said the poet, and Alice McKinley would agree. April is a hard month. Not that she doesn't have some fun. It does begin with a wonderful April Fool's Day joke on her brother, Lester. But it also begins with Aunt Sally reminding her that she will soon be thirteen (as if anyone could forget something so important) and then she will be Woman of the House, since her mother is long dead. It is an awesome responsibility. All her life she had assumed that her father and Lester were there to take care of her; now she is going to have to take care of them. Taking care of Lester, alone, could be a full-time job, she thinks. Being Woman of the House has all sorts of drawbacks. For example: It never occurred to her that when she suggested her father and Lester ought to have physical checkups, her father would insist that she have one too. How could you let a doctor see you naked?

Of course, Alice is still in school. And there she faces another crisis. She might be Woman of the House at home, but in school she needs a different kind of name, one given by a table full of boys in the cafeteria Depending on their figures, girls are being given state names -- some states have mountains and others do not. Will flat, flat Delaware or Louisiana be her fate? Alice lives in fear that it might be, though even worse is the fear that she might not get a name at all.

The month ends with a dinner party for her father's birthday (part of being Woman of the House) that has more downs than ups -- and with a totally unexpected event that makes Alice and everyone she knows grow up a little and wonder a little deeper about life and the future. April is a hard month, but reading about Alice in April is to find that most tragedies (though not all) pass and tears can turn to laughter and delight.