Firefly Lane tells the story of two girls, both dealing with their own pain, who bring their guard down long enough to become best friends. This friendship continues through their ups and downs over the span of three decades. Kate Mullarkey is the shy girl, with thick glasses and a retainer. She feels lonely and uncool.
https://www.amazon.com/Firefly-Lane-Novel-Kristin-Hannah-ebook/dp/B000V77082