Like in Love with You by Emma R. Alban

Mean Girls meets Northanger Abbey in this Sapphic, rivals-to-lovers Regency Romance that begs the question: what if Cady and Regina just… kissed?

When country-bred Catherine Pine relocates to Bath in 1817, she and her mother come face-to-face with her mother’s arch nemesis, Lady Tisend, and her daughter, the wildly popular and gorgeous Lady Rosalie. Though once her very best friend, Mrs. Pine alleges Lady Tisend ultimately did her a great injustice. Twenty-five years later, she sees the perfect opportunity for retribution:

Catherine will win the favor of Lady Rosalie’s suitor, Mr. Dean. Together, Catherine and her mother will ruin the Tisends’ lives, secure Catherine a fruitful match, and launch a fully triumphant return to Bath. It’s the perfect plan for revenge. Only Catherine soon discovers that there’s more to Lady Rosalie’s mean streak than meets the eye. Lady Rosalie is by far the wittiest, cleverest, most intriguing young woman Catherine’s ever met, and she’s utterly smitten. 

Meanwhile, Rosalie feels trapped in her perfect life as Bath’s favorite daughter and resident mean girl. There’s no challenge anymore, no excitement, no surprise. But when she notices newcomer Catherine gunning for her spot as queen bee, Rosalie finally feels a spark again. She determines to meet Catherine’s challenge with gusto, because Catherine ignites something in her. Something Rosalie absolutely doesn’t want to extinguish.

As their mothers force them into increasingly absurd contests of wit and feminine charms to win Mr. Dean’s affections, Rosalie and Catherine instead find themselves falling for each other, scheme, by barb, by catty jab… 

Can their sizzling rivalry really become a match to last?