I am right there with you. I am a little over half way through my 30th year of life. I have "wasted" a lot by having a ton of fun and enjoying myself, while also getting plenty done professionally. I am excited about the future, and also intrigued with this concept of another 30-50 years of productivity, but like you, sometimes I can accept a fate of being 'finished'. It's weird, but not in a morbid way, more like a, "I'm so blessed to have been able to do all this amazing stuff" kind of way.