Across the pond / Joy McCullough.

Enhanced descriptions from Syndetics:

From the author of A Field Guide to Getting Lost comes a heartwarming, "emotionally perceptive" ( Kirkus Reviews ) story about new beginnings, burgeoning friendships, and finding your flock.

Callie can't wait for her new life to start. After a major friendship breakup in San Diego, moving overseas to Scotland gives her the perfect chance to reinvent herself. On top of that, she's going to live in a real-life castle !

But as romantic as life in a castle sounds, the reality is a little less comfortable: it's run-down, freezing, and crawling with critters. Plus, starting off on the wrong foot with the gardener's granddaughter doesn't help her nerves about making new friends. So she comes up with the perfect solution: she'll be homeschooled. Her parents agree, on one condition: she has to participate in a social activity.

Inspired by a journal that she finds hidden in her bedroom, Callie decides to join a birding club. Sure, it sounds unusual, but at least it's not sports or performing. But when she clashes with the club leader, she risks losing a set of friends all over again. Will she ever be able to find her flock and make this strange new place feel like home?