Watch: Britney Spears' Niece Maddie, Daughter of Jamie Lynn Spears, Reveals Her College ChoiceJamie Lynn Spears' daughter Maddie Watson isn't worried about her freshman 101s. After all, the 17-year-old-whom Jamie Lynn shares with ex-fiancé Casey Aldridge-recently started her senior year of high school, and she offered a look into her special day. In her Aug. 19 Instagram post, Maddie proudly held her "first day of 12th grade" flag while wearing her school's uniform.