I'm definitely in the "Do it now!" Camp, but only if the PCT thruhike is the dream burning in your mind. If you have done an AT thruhike, you should be familiar with focusing this passion. If FIRE is the real passion, and another thruhike is an expression of that passion, then do FIRE first... maybe...
Remember those week-long slogs in the rain? Remember how your friends & family must have been exhausted from hearing every little detail of your hike, but supported your dream? Remember how the fear of telling them you just "quit" drove you on at times? You need that level of passion and focus to make it to Kennedy Meadows through the desert!
Given the ability of life to derail our big dreams with the randomness of major illness and injury, I chose to "Seize the day!" My perspective was different from most since a long life was not a given for me due to having cancer in my early 20s. Statistics for survival to age 50 didn't looks all that good for my particular cancer, but I had a new treatment protocol. (I'm mid 50s now, and hoping for 90+ with excellent health.)
My employer gave me a 6 month leave of absence AND PAID FULL BENEFITS for my first AT thruhike. My second AT thruhike occurred a few years later when I received a nice severance package from another small startup. A few years later, I gave "2 Years Notice," that I would be leaving to hike the PCT (and later the CDT). (I outlasted the management team, and my notice actually saved a coworker in a layoff.)
Definitely consider the cultural fit on the Trail. While the PCT isn't as social as the AT, you will still find the interactions and shared suffering with fellow hikers a source of encouragement and entertainment. The hikers tend to be either under 30 or over 60. I always felt a bit out of place in my mid 30s and early 40s, even though I was often assumed to be a decade younger. (This is one of the few pleasant social side effects of being short -- we are often thought to not have grown up, yet!)
I realized there were time windows in my life that let me disappear for 5 - 6 months, maintain health insurance (pre-ACA), and sometimes provided financial benefits. Shortly after my CDT hike, my parents health went into sharp decline. The window for disappearing for 6 months has now been closed for most of the past decade. My adventures take new forms, and I regularly disappear into the mountains for about 4 weeks a year.
I had always said I was on the "many mini retirements plan," but later decided "retire early, retire often" better explained my way of wandering through life. in tech I have found a niche as someone who isn't afraid to take a risk. With the ACA I don't have to be tied to a W2 paycheck, and can now work contract if something interesting or fun comes along.
My primary goal has never been FIRE, but rather to manage my financial life to serve living. This resulted in the same frugal habits with wise investing. About 4 years ago I realized I could truly be financially independent with a few tweaks. Tweaks have been made.
