I hear you. Fresh out of college, I figured I was smart and impressive enough to find a way to retire by 50. Preferably by becoming a world-famous novelist in the next few years, or a dot-com millionaire by the turn of the millennium. Basis: nothing but wishful thinking, and the belief that I sure as hell couldn't keep doing this work crud five days a week for half a century. (Oh yeah, I can also distinctly remember telling my brother, "I really think I'm meant to win the lottery. I know the odds are against it, but it should happen to me.")
By 35, married, dual income, no kids, I had a plan, based on actual, mathematical evidence (if with some optimistic assumptions) that I could retire at 60, with a paid-off house and a decent retirement fund.
In my mid-forties with kids and a spouse that stays home, past one really terrible financial mistake with a house, plus several minor financial setbacks at work, I'm now looking at 65, more likely. I still have my doubts about the sanity or feasibility of doing this work crud five days a week for a few decades, but at least I've now worked almost half of the mandatory time, so there's that.