Read first, or watch first?
Read first if your reader can manage it, for a concrete reason: the films give away the two turns the book spends hundreds of pages earning, Beth's story and the answer to Jo and Laurie. For the film order itself, the 1994 version tells the story straight and makes the better introduction; Gerwig's 2019 film rearranges time and rewards someone who already knows the book, which makes it the perfect one to watch after. This is a long book for strong readers, and the movies are a fair companion for a middle-schooler working through it.