Twelve-year-old Tahlia Wilkins is ready to start off her perfect summer when dreamy crush invited her to his birthday pool party. But the Red Goddess of Panties, a.k.a. her first period, arrives twenty-four hours before the pool party and completely messes up all her plans. To make matters worse, her mom is out of town, and there's no way she's going to ask her awkward dad for help! Thalia was always afraid growing up would be tough, but this is just not fair.

In order to save herself from total embarrassment, it will take all of Tahlia and her best friend Lily's scheming to keep her reputation and her favorite pants from being ruined. Sneak off to the grocery store to buy the 'goods' only to have the clerk price check your tampons over the loudspeaker? Trick your big-boobed teenage neighbor into letting you use her bathroom to 'rehome' some tampons? Take a dip into a fountain to 'borrow' some quarters for a bathroom feminine product dispenser? Check, check, check!

After surviving hijink after hijink, the pool party goes off without a hitch ... that is, until Tahlia learns her life is changing all over again, only this time it's worse than a period: Lily's moving away and everyone knew before she did!

With the hilarious and heartwarming tone of the movie Eighth Grade and Dork Diaries, Grow up, Tahlia Wilkins! is a coming-of-age middle grade novel that teaches readers about accepting change, whether it be physical, emotional, or mental.