Forgot My Sister's Birthday By Accident Twice In A Row? Oops!

So, here's the thing. I know everyone says they're bad at remembering birthdays and anniversaries and all that stuff, but it's one thing to admit you forgot out loud and another entirely to actually do it twice in a row for the same person. And my sister is not someone who's going to just let this slide either. She's like a superhuman memory machine when it comes to family dates, she always knows exactly which anniversary of what we're talking about. I thought I had everything under control this year, I set an alarm on my phone for the exact day, and even checked the calendar twice just to be sure. But somehow, despite all that, I managed to skip over her birthday like it was no big deal at all. And last year? Well, same story really. Now, I'm not saying she didn't get anything nice from me. Oh no, she did! I bought her a lovely gift and everything on the day after, and then explained it as if it were some super cool spontaneous gesture because apparently that's way better than just forgetting. But honestly? It was pure panic mode trying to figure out how I'd missed it all over again. I keep telling myself it will be different next year, but really? My brain is pretty sure this could happen every single year unless I get a tattoo of her birthday on my forehead or something. Anyway, just thought I should confess and maybe put some sort of curse on myself so that I don't mess up again. Anyone out there have any tips for an absent-minded person trying to be present for the important stuff?