That's difficult to answer because it really depends in how work them out. I would say try to lose fat a strong core is already there if you workout regularly, and then focus on building lean muscle even though you do want to target the core muscle try to vary your workout regimen with time intensity and the exercise. hopes this helps
Follow me I'm a personal trainer and my specialty is abs I have a couple of workouts that will help you but u need to make sure you also do at least 30mins of cardio 5 days a week and eat clean. Good luck!!!