Reference Deadline

If one of my references don't submit the letter of recommendation by the personal deadline I give them, should I message them and remind them about it?

I put in my references as soon as PTCAS opened. My prof asked to give her 3 weeks between when I put her into the system and when I put my personal deadline. I gave her a little over 3 weeks, so the deadline is tmw. I have done everything else on PTCAS so I'm just waiting on her so that I can submit my application. I don't know if I should message her if I don't hear from her after tmw or if I should wait it out more. I just want to make sure I'm not being pushy and that she knows I'm appreciative of her help, regardless if she doesn't do it on time (but at the same time, I'm eager to submit my applications).