I have never, ever minded a birthday. I will celebrate from the first day of the month until the last day. At my age, I've always felt you get a birthmonth, not a birthday. I will plan a birthday party for myself in a heartbeat. In other words, I'm not usually self-conscious about my age or my aging.
This year, though, I am not so excited. And I think it all has to do with my thing for numbers. My birthday number feels odd and old and undesirable.