It means she was thinking about you. That's pretty much it. You must remember, MLC=confusion. They don't make sense and trying to make sense of their statements is a sure fire way to end up in the loony bin (do they even have those anymore?). You can take comfort in knowing she WAS aware of the date and its significance. But reading anything more into it (even the admittedly odd use of the word celebrate) is not worth it.
"Love me when I least deserve it, for that is when I need it the most"
M18 Me39,H42 D16 Bomb 1/10 Moved out 3/10 OW 6/10 H wants to R,OW gone 11/10 H moves back 5/11 H wants to wear rings again 9/11