Quit before or after?

I’m feeling a bit torn. This is my third year and I’m still an associate. I’m planning to leave public accounting, but I really want to let one manager know before I go. I was thinking of giving my official notice to HR on January 3rd because of the holiday paycheck timing, but I’m considering letting her know before the holidays to give her a heads-up. Would it be a good idea to message her on Teams next week and then submit my notice to HR on January 3rd?