It was shipped to theatres under the name "Sugar and Spice".
When Jenna is flipping through her mail just after waking up as a 30 year-old, one of the letters is from Sparkle.
Originally Young Matt was to be played by Jack Salvatore Jr.. Test audiences reacted negatively towards him and the girl originally playing Young Jenna (Shana Dowdeswell), so the parts were re-cast and the scenes were shot again.
The Poise article that Jenna is reading at 13 ("Thirty, Flirty & Thriving"), features the apartment that she later lives in at 30.
The blindfold Jenna is wearing when she is 13 is made out of the same material/pattern as the eye cover she is wearing when she wakes up when she is 30. The blindfold and eye cover were both designed by Cris Notti, an accessories designer based out of Los Angeles.
In Australia, the title was changed to "Suddenly 30" because distributors thought audiences would misunderstand the original title.
The scenes on Jenna's 13th birthday were shot twice with two different wardrobes. In the movie trailer young Jenna is wearing a multicolored top and has her hair down but in the movie she is wearing a blue top and her hair is up.
Jenna's birth date is 26 May 1974.
When Jenna hides in the closet at her thirteenth birthday party, pictures of her growing up can be seen on the back on the door. These pictures are actually of Christa B. Allen, the actress who plays thirteen-year-old Jenna.