When I was 22 to 24 years old, I worked in a backpack/ski shop in the burbs. We had our regular customers and because we led 8-day backpacking trips in the Sierra in the summer, we'd get to know many of them pretty well. They were all middle aged (like you and I are now) and financially successful enough to live in the burbs and shop locally.
NONE of them said, "Get back to school, start a real job, get a mortgage, and settle down real soon."
MANY of them said things like, "I went right to work after school, got married, bought a house. Now I have the bank account, gear, and the shop full of tools I wanted when I was younger, but no time to use them. Keep doing what you're doing for a few more years." because we'd chat about trips and twice a month I'd jiggle my schedule for a week here and 5 days there and take a backpacking or road trip somewhere new. Whereas they'd dedicate one of their few weeks of vacation to go backpacking with the groups we'd put together and look forward to all year.
You say you have a plan and but it is unclear to me if you are selling the house before or after the thru hike. I'd suggest selling it before. Reduce the mementos to a few boxes in Mom's basement, loan the few sentimental pieces of furniture to friends and family. Craigslist or Goodwill the rest. The freedom to have an open-ended agenda is remarkable. The housing market is once again quite hot so it is a good time to sell. If you sell before you are ready to start your hike, then coach-surf if you have some weeks on the job left or do a road trip with the dog until it's time to start hiking. Get a minimal cell phone plan and imagine life without mortgage, home insurance, electric, gas, water, sewer, and cable bills.
Having done this a few times, (admittedly only once involved selling a house), I found the freedom invigorating and all sorts of opportunities for trips, friends and temporary employment popped up that I never would have imagined (i.e. had blinders on to) while in town, at work, in my regular routine.
You'll bug the hell out of people when they ask you when are "coming back" or "getting on with your life" if you say "I don't know" or "when I'm ready" or "I think this IS part of my life.", but, hey, maybe it will put a bug in one or two of them to do likewise someday.