My laptop was repaired and i was signed into my mom's... and now all her passwords and mine are mixed together on my personal laptop.

My personal laptop was being repaired, and I was using my mom's old laptop until mine was fixed. I logged out of her Mozilla account on that laptop and signed into my own. Now that I have my personal laptop back, all of my passwords, bookmarks, and extensions are mixed in with all of hers. I don't know what to do, and I'm worried that if I remove bookmarks from my account, it'll create a domino effect that results in a catastrophic Mother's Day.... Please help, I'm not good with technology, I'm just a geology major.