Not in the least, but I'm not a birthday person at all. I know my immediate family's but that's it. I have a vague sense of in-laws, nieces, etc. I don't know when my friends have birthdays. I'm just of the mind that once you are older than 18, it's just not a big deal. My family feels the same way, birthdays are for kids. If my friends are hurt by that, then they need to tell me a week ahead of time so I can remember and say something. Otherwise, it's just not on my radar. I'm happy to celebrate, do something nice, whatever; but it's just not something I pay attention to if you are an adult. Kid, yes. I know my friends children's birthday's.
If it is important to you, then it is perfectly reasonable to be sad, especially since she's has acknowledged it in the past. In general I think you have to let people know that it's important to you so they have a chance to do something nice. Next year maybe mention to your friend that your birthday is next week and you'd love to celebrate with a coffee date? I'm not sure that telling her she forgot would accomplish anything other than making her feel bad.
Carrie
DD#1 September 2005
DD#2 October 2007
The good thing about science is that it's true whether or not you believe in it.
-Neil deGrasse Tyson