Is this buccal fat or premature jowls? (Photo)

Enlarged buccal fat removal causes fullness of the Lower anterior cheeks next to the corners of the mouth, but does not affect the jaw line nor the jowls.Jows are accumulation of both skin and fat at the jaw line close to the vertical line from the corner of the mouth. Most of the time this is secondary to sagging o the facial skin due to decreased cheek bone fullness in young patients ( late 20s, 30s) and also to laxity of the skin in patients from the late 30s and above. 

Buccal fat excision is an appropriate surgical procedure for patients that of overly full and wide cheek areas. In common terms, it is good for patients who have chipmunk cheeks. In reviewing your pictures, is difficult to tell if you're a good candidate because your cheek area is slightly full but not overly full. Liposuction can also slim the face and jawline. You are a patient that would need an in person consultation for a complete evaluation and explanation of the positives and negatives of these procedures in your situation.
Concentrate on preventing sun damage by protecting your skin with sunscreen, hats and clothing. Have your dermatologist recommend a medical-grade skin care regimen with retinol and hyaluronic acid. Get regular chemical peels. If you do start to see some jowling, a mini lift, with or without a neck lift would give improvement. I hope this helps.

Buccal fat pad removal is for overly filled cheeks. From the photos, it seems as you are asking more about the jawline. The jawline, at your age, can be addressed many different ways from non-surgical methods(Kybella) versus surgical methods of liposuction. I would recommend seeing a board certified plastic surgeon and getting a consultation to see what your options are. Good luck!