I didn't find anything objectionable, but these are the parts that some adults may have found unsuitable:
1. Emily's mother has a "soul-mate friend." "Aunt Chester is not her real name. It's Emily, like mine, but in high school her bazoombas suddenly inflated 'like a life raft off a sinking ship' - Dad's saying - and the name just stuck." Later, we learn that Emily's mother's missing earrings once turned up under Aunt Chester's bed. So, mention of breasts and - very big stretch - possibly a lesbian relationship between the two women. But Emily's parents are still together and Aunt Chester moved to another town four years earlier.
2. Emily's gym teacher, Ms. Clark is "tall, very pretty, and maybe a lesbian. She has a photo on her desk of her and another woman posing in front of the Eiffel Tower." When the students ask about who she is, they are told she is her roommate. "Janelle tried to start a whole Ms. Clark-is-a-weirdo-lesbian rumor, but Carol put a stop to it right away. Carol said that she thought lesbians were cool and that anyone who made fun of them was shallow and a discriminator." Emily writes, "If I were a lesbian I'd pick a girlfriend who was exactly my size so we could share clothes. Maybe that's why Ms. Clark has such an amazing wardrobe." A positive portrayal of lesbians, no matter how minor the character, is a red flag for some people.
3. Emily recounts the time she and her best friend, Sandra, spied on Sandra's older sister by looking into her bedroom from the garage roof while their parents were out of town. "It was uncomfortable weird - Claire had all her clothes off except her underpants, and Brad wasn't wearing his shirt. Sandra just freaked out! She jumped off the garage like a superhero and ran into the house shouting Claire's name. We waited for them in the living room. Claire seemed really nervous, and Brad didn't even look at us; he just left." This hint of sexual behaviour between older teens seems mild enough for readers as young as 9 or 10.