Will this work for a flat tummy in time for my navel piercing?

i’m going to get my navel pierced in exactly a month from today…but the thing is, i don’t have the flattest tummy, i’m not what you’d call ‘fat’, but my tummy is "fluffy" if you know what i mean. and i was wondering that if i did 24 sit ups every night, will i have a satisfying tummy in time for the piercing?