Susin Nielsen 
Tremendous Things [EPUB ebook] 

Wilbur is sure he’s a loser: he spends his life being bullied, his best friend is 85 years old, and his only talent is playing the triangle in the school band. But things start to look up when he gets the chance to be part of the French exchange. Wilbur’s billet Charlie arrives to spend the week with him and his two moms . . . and it turns out that Charlie is a girl. An amazing, sophisticated, French girl who Wilbur instantly falls in love with.
Keen to win her heart, Wilbur agrees to a total life makeover before he sees Charlie again on the return trip to Paris. But the course of true amour never did run smooth . . .