It's Shinobu from Monogatari Series! The character is well liked by anyone following the series. The mug features 6 different ages of her, starting from her child form with the goggles (seen in Bakemonogatari), progressively up to her adult form holding a replica of Kokorowatari.
She's also known as Kiss-Shot Acerola-Orion Heart-Under-Blade.
Monogatari Shinobu mug clearance merchandise