The Very Secret Society of Irregular Witches by Sangu Mandanna

Mika Moon is a witch who lives a solitary life in Brighton. When she's contacted about taking a job in Norfolk as a tutor for three young witches to help them learn and control their magical powers, she decides to take the position. The girls--Rosetta, Terracotta, and Altamira, live at Nowhere House with Ian and his husband Ken, housekeeper Lucie, and librarian Jamie. The girls' adoptive mother, Lillian, is an archeologist who spends her time travelling the world, leaving Jamie in charge of parenting duties. The household members are quirky and welcoming to Mika, except for Jamie and Terracotta who resent her presence. Slowly both begin to warm to Mika, especially Jamie, and it's obvious to all of a possible romance. The Very Secret Society of Irregular Witches is charming first novel full of humor, love, and togetherness.