It's hard to say. I usually test out to INTJ, and I'm one of the ones who wanted to keep working, I really liked my job, but my last contract ended and that was it.
Now, I didn't retire at 40. Talking with other retirees, those who were self-directed keep being so, and those who needed outside influence to get them going still need the outside "push". So some self-reflection is needed re that.
What I have found is that my life has shifted in unexpected ways - I am getting heavily involved in what were peripheral (very peripheral, on the back-burner) activities, and the things I thought I would miss a lot I only miss a little. And that is after not quite a year. At this point my life has changed so much over the last 5 years, I have no idea where I will be in another 5 years. For someone who used to try a lot to plan ahead, that is a very odd (but somehow freeing) feeling. "Go with the flow" has a new meaning now, life is more relaxed and less urgent - not that there are no deadlines, because there are, but the "rush-rush" is less so. Opportunities present themselves now that are different from those that popped up while I was working.
Of course you will be younger at retirement, so YMMV.