The innate “girlhood” of this movie has been overstated. It’s been messed around and joked about. “Lux Lisbon core”, “obviously doctor you’ve never been a 13 year old girl” are among the trends. They unwittingly fetishize the very piece of media they claim to relate to and cherish; mirroring the exact story of the film. 
Although it’s frustrating and annoying, it’s just following suit with every other attempt to feel connected to something. We can’t say they don’t relate to them, who knows. 
I felt the same way when I first saw it. 
It’s not unique that this was a pivotal movie for me, in fact it’s a bit cliché. Everything was aligned, I was Cecilia’s age, I live right by Grosse Pointe, I read the book in the bathtub, wrinkling the pages with steam. I thought in that very still place in time, “This is about me. I am meant to see this.” 
It was a very transitional period of time, and filling that space with this, both the book and the film, has created a sort of vortex. I’ll see a frame from it, the cover of the book, my Dreamboat Annie record, and suddenly I’m in 8th grade again.
I always want to ignore that period of time. I see it as a point where I was obnoxious, rude, embarrassing. But I cannot wipe away the parts that led me to where I am now.

“...I think we are well-advised to keep on nodding terms with the people we used to be, whether we find them attractive company or not. Otherwise they turn up unannounced and surprise us, come hammering on the mind's door at 4 a.m. of a bad night and demand to know who deserted them, who betrayed them, who is going to make amends. We forget all too soon the things we thought we could never forget. We forget the loves and the betrayals alike, forget what we whispered and what we screamed, forget who we were.”
- Joan Didion, Slouching Towards Bethlehem

This movie is that hazy, still point in time for me. There are times like these where I wind up sick, running on three hours of sleep, on the couch, and I realize I’m at a point where I must look back. I cannot pretend I am past the point of thirteen when I am ever as close to the Lisbon girls.