Girl of the Year 2025 Summer McKinny's journal has been spotted on Amazon with a release date of September 17, 2024. The author is Clare Hutton, who wrote the Like Sisters series for American Girl.
I did some research, and there is another Clare Hutton who is a specialist in Irish literature, meaning Summer will most likely be Irish-American. Additionally, Clare is white, meaning the chance of Summer being African-American has effectively gone out the window, as AG usually has authors that share the racial identities of their characters.