How late is late? I saw the light in my last year of law school (though I didn't discover MMM until later), at 26. It was less about seeing the light of frugal living, more about "oh jesus h christ, I've been eating out and spending a ton of money on stupid stuff, but I owe Sallie May $200k at 6.8%-8.5%, WTF HAVE I BEEN DOING?! I'VE BEEN DEBT FINANCING MCDONALDS." That got me focused on paying off that debt, to the point where I got a $50k signing bonus and applied every penny--other than money I used for an engagement ring--to the debt.
Then, by the time I killed the debt, I had a bit of the frugal living/ER bug, and also became lazer-focused on saving money to buy a house. The hitch: I have no idea where I will be buying said house, so I have no idea how much money I need for a down payment. Could be $40-80k (in the midwest), could be $200k-$400k (if we land in New York, S.F. area, or D.C.). I'm still about 180k away from having the cash for the upper end of that range, so even if I didn't have a bit of the ER bug, I would feel very constrained in my spending.
Hoping that once the house thing is situated, I keep the ER bug and keep on my current path.