I've been 30 for exactly two months now and I was more affected by it in a negative way than I expected. But then I tell myself that I'm "only" 30 and usually that does the trick until something else gets thrown my way.
30 didn't bother me. I'm going to be 35 in September, and I feel like that should bother me more, but it doesn't. I look at my H and I and I really have a hard time believing we are in our mid-30's. In my mind, we are still 27, 28.
I am also in disbelief that my parents are both over 60. In my mind, they are in their early 50's.