Continuity mistake: In her apartment Jenna walks out into the hallway, looks at herself in the mirror and stumbles backwards over the shelf behind her. There is a short stack of magazines on that shelf, yet when Jenna looks at herself in the mirror the stack of magazines is at least three times as high in the reflection.
Continuity mistake: Towards the end of the film, Mattie hands Jenna the dream house he made for her 13th birthday. There is hardly any "wishing dust" on the roof. However, when she goes outside and sits on her front porch, there is plenty of wishing dust all over the roof of the toy house now.
Continuity mistake: When the six girls arrive for the party, in the first shot Tom-Tom tosses her blue jacket, then the second girl lays her red jacket and the third girl starts to put her pink jacket into Jenna's arms. Yet, at the start of the next shot facing Jenna, she holds only the blue jacket, since the red jacket is gone, the pink jacket is placed in Jenna's arms on top of the blue jacket and then the red jacket is thrown into her arms from off camera, before the rest of the girls dump their jackets into her arms. Then in Jenna's close-up, the jackets are positioned very differently in her arms.
Visible crew/equipment: When Lucy closes the car door after Jenna finally gets in, you can see the microphone and microphone pole through the reflection of the car.
Factual error: When Jenna first wakes up 30 years old and calls her parents, she dials 7 keys on the phone. Since her parents are in NJ and she is in NYC, she would've had to made 11 keystrokes (1 + areacode + 7 digit phone number) to get to their voicemail.
Continuity mistake: When Jenna first sees herself in the mirror as 30 she falls over the side and then looks over it into the mirror. In a shot facing her, only her left arm is on the side. Then in the next behind shot now both her arms are on the side. When it cuts back to the previous angle only her left arm is on the side again.
Continuity mistake: When Jenna first realizes that she is thirty and she walks down the hallway, there is a pile of magazines on the counter with the mirror. Then in the next shot, the pile of magazines isn't there.
Continuity mistake: When Jenna enters her office she throws her silver bag on a chair, and as she walks over to the photos you can see the bag is laying on it's side. When the woman knocks on the door you can see the silver bag again, but now it's standing upright, as you can tell by the straps/handles.
Continuity mistake: Jenna's white drink at the party repeatedly changes - the amount of drink inside rises and lowers between shots.
Continuity mistake: When Jenna asks the DJ in the party of Poise to play "Thriller" he starts dancing. Then, there's a closeup to Jenna and we can see that the DJ is not dancing anymore. In the next shot, he's there, dancing again.
Other mistake: Wendy loses her accent and it changes at points, such as when she asks Matt if he's hungry.