Outside of a some hairstyles that need to be unlocked, initial character creation gives you every option you'll ever get for your body. So if you didn't find it there, then it doesn't exist in the game. So if you want a curvier character, the only way to get that is by switching to a curvier race by using a Fantasia, which is an item that allows you to entirely change your character without losing progress. There's a quest in the game that allows you to get one for free; after that the only way to get more is to pay real money in the cash shop.

As Brightamethyst said, you can use the Aesthetician NPC (once you unlock him) to change more minor aspects of your appearance like hair, makeup, default earrings, etc.