I'm going to say don't acknowledge it, at least not to her.
Since it is a special day for YOU, maybe treat yourself to some radical self-care. Do something that's fun for you, call a friend and treat friend to a nice dinner, see a movie, but above all, plan the day to be as full as possible, so your mind doesn't have a chance to go there.
My 13th was a week ago today, and neither of us acknowledged it. He must have remembered at some point in the night, b/c the next morning I had a text that said "I totally $ucked up, and I am so sorry."
Not really anything I needed to say back to that. And I've not heard from him since, except for a missed phone call Saturday night (probably to check on the house due to Hurricane Nate) but no message or text when I didn't take the call.
I think based on DB principles, it's best to not contact her. If it means anything to her, she will message, but I wouldn't have any expectations. And anything you do towards her will be seen as pursuit and probably not accepted in a positive light.
It sux, I know. Believe me, I know.
M-60 H-51 M-14 years BD 12/26/16 S 1/1/17
"First the pain, then the rising." Glennon Doyle Melton