Ask yourself what you're waiting for and then consider how much it may be affecting your happiness level. Whether you're waiting for the traffic light to turn green, the perfect job offer to arrive or the spiritual leader of the Tibetan people to speak, give yourself a breather. Don't consider it waiting. Consider it a chance to be mindful and thankful for life.
I wish I could delete the moments where I ever felt "old" because to think that now is just stupid. I saw the number 24 written on the cover of a book while on the train, and clearly thought these three things -- I am older than that number. I have not read that book. There is so much I have yet to do.
Everyone my age has some dangling worry trailing around after them everywhere that they're somehow not doing everything, that what they're doing is not altogether the right thing, that they are missing out. The doubt is natural, and everyone you know -- yes, even that person -- carries it sometimes too.