It's really difficult to add much commentary to Nathan's statement because it stands on its own, has undoubtedly crossed your mind at some point, and is something that everyone needs to hear regularly.
It's so easy to self reflect with questions like "What am I doing with my life?", "I can't even qualify for this I'm too old", "I wish I would have done more," and "I'm never going to be that successful”.
So rather than comparing your life to 30 people, ask yourself questions like: "Do I feel content in my work?", "Do I feel valued at my job", "Are there some things I can do to improve my career?", and (my favorite), "If you could tell the 21 year old version of yourself what you're doing now, would they be impressed?"