The President’s Daughter series by Ellen Emerson White.

I read this series for the first time in 1995 as a 5th grader and fell absolutely in love with the sarcastic shy and historical nerd that is Meghan Powers. There were three books then, but in 2008 the books were lightly updated and a fourth book was published, and they are still my absolute favorites. I buy used copies whenever I see them and give them to girls in middle and high school and they’ve always been a huge hit. I still dream of someone making a movie of these.