What's the Name of That Book??? discussion

Ironically enough I really only remember that this book is about two women in a nursing home that undergo suspicious clinical trials and are now young again or no longer dying. They have to keep several journals throughout their “new life” as the brain only has so much space and they’re make new memories. The people who did this become the enemy and they’re hiding from them. I remember a car crash happening at some point maybe later in the series if it is a series? When one women is trying to run away. But I’m pretty sure by that point they were hiding off grid for a bit? I read this at my middle schools library late 2000s no idea publishing, author, or cover art.
Hope I didn’t leave anything out please help me and ask any clarifying questions

I’m also pretty sure a lot of time passes throughout the book or series and it’s not a short span

Were they aging backward, and forgetting anything past the age they had reached? I think I've read this book but also can't remember the name.

Is it Turnabout by Margaret Peterson Haddix?

Turnabout for the link

Bridget wrote: "Is it Turnabout by Margaret Peterson Haddix?"

yes this is the book!! thank you