I turned 40 a couple weeks ago and I'm good with it. I try to stay current with music and fashion, but I never feel like I'm chasing youth (although a couple of my recent haircuts might be pushing it).
I'm cool with the grays coming in. The loss of athleticism bothers me, but I'm altering my basketball game to fit my new reality. We'll probably be relocating in the next few months, and will probably have to live in the suburbs for the schools. This actually bothers me a lot, but I'm not sure if that's tied to letting my youth go or not.