On my 14', it was held on via a few plastic tabs that will pop free and some double sided tape. While heart rending, I heated it up with a hair dryer then used a wide flat head screw driver and a credit card to protect the edge when prying. For my part, I kept a visual in mind of constant pressure of easing the tape up. First time is the worst. I've pulled mine off a few times since to try some different things. You'll be fine.
2016 Mustang Ecoboost Premium, Performance Package: Roush Quarter Window Scoops; Roush Jackal Rear Spoiler; Modded GT Wire Mesh Grilles; Eibach Pro-Kit Springs; Mishimoto Oil Separator; MAPerformance CAI; MBRP XP Catbacks; Drilled and Slotted Brake Rotors; BAMA 93R Tune; Royal Purple juice in everything!