Nikki Bella is working on her post-baby body!It's been five months since the 37-year-old star gave birth to her and fiancé Artem Chigvintsev's first child together, son Matteo. On Friday, the new mom showed off her post-birth figure, writing, she's «getting there» and is «finally going to start workouts.»In the Instagram Story mirror selfie, Bella rocks comfy grey sweatpants and lifts her white long-sleeve shirt up to show her stomach.