Here's Alina Starkov as described in the Shadow & Bone books:
As a child, she was described as being "pale and sour, like a glass of milk that's turned." She's skinny, has "dull" brown hair, shadows under her eyes, and "sallow skin." After coming into her powers, she becomes healthier, her hair grows thicker, and her skin gets tanner. She's 17 years old in the first book.