I discovered FIRE and MMM only a little over a year ago at 47 years old. Up until that point I had assumed I would live my entire life in debt and had no hope of ever retiring. Despite a reasonable salary, my expenses have always been high (single income household with 2 kids in a HCOL area). Yes, these were all my choices and I fully accept them. I was raised by parents with zero financial sensibilities, and until a few years ago, completely distrusted equity markets.
At 47, all that changed, And while FIRE is likely off the table for me, implementing mustachian values and boglehead methodologies has rapidly propelled me in the right direction. The slope of improvement is steep, but starting in the red, my journey to FIRE will take some time.
I do find that some of the advice and comments posted here on MMM, by younger users, just have little applicability to my situation. For example, holing up in a van in the Walmart parking lot to save on rent is just not practical for me for a multitude of reasons. And i agree with one of the posters upthread, that even discovering FIRE at this later stage in life is of tremendous value. I am happier, less anxious, more determined, understand better what I value in life, and have modified my behaviors to be in line with my values.
I've read an insane number of books on FIRE over the past 1.5 years and feel tremendously empowered (YMOYL, The Milliionaire Next Door, The Four Pillars of Investing, etc.). Engaging this community on a regular basis keeps my moving in the right direction.