One Piece: Brains Against Brawn

If one day I became Ace's younger sister, would I take my life as lightly as Ace does, or just go with the flow? Well, well, I'm already here, so I might as well save this rotten world. (This is a personal indulgence, and the characters may be out of character. I'll try my best. If you're impatient, it's best to start from chapter 100.)