Factual error: After putting Jenna in the closet, everyone crowds together and plan to leave. One girl holds a diet coke can, which is obviously a more modern design, and not from 1980's. (00:10:30)
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. (00:15:20)
Factual error: When Jenna looks at her mail, her address is 61 5th Ave, 7C, NY, NY. When she goes outside, you can see, she lives at 51 5th Ave, NY, NY. (00:15:20 - 00:16:57)
Answer: Jenna asked the girl, "Can you tell I'm wearing underwear? Because I totally am". This is because when she was 13 just a day before, she was wearing big underwear. Now she's wearing a thong, which wouldn't be visible when wearing a dress.