I do not posses the wisdom
I do not posses the wisdom and experience of others older than me here, so I can only speak from my own point of view and my own story.
As I am still recovering from "analysis paralysis", I say ask yourself only one question - do you like model trains?
If it's something you've outgrown then move on, don't dwell on it as you are only wasting your time. Maybe drones with aerial photography, or RC boats are your cup of tea, or maybe something else altogether (knitting, woodworking, community work, whatever).
Yet, if you like model trains, select the scale not for its value of bang for the buck, or amount of trackage it gives over others, or what some "expert" tells you, all of that is noise. Select it because you truly like it, deep inside.
Long time ago I played with H0, then, when I came back to the hobby several years ago, I thought I'd restart with H0 again by buying some equipment and track.
Then came many other voices that persuaded me that N would be better suited and would give me a railroad empire in the space I have (23'x13'). So, I went ahead and bought N equipment, and I struggled for months to work with it, trying to force myself to like it. My heart just wasn't there...
At that point (this past March) I finally parted ways with N scale. I am now stuck with a lot of track, turnouts and equipment in N scale (that I need to sell) but I went back to H0 because that's where my heart was. Since then, I've been slowly undoing the year of planning and construction I did in N scale (you can see the progression on my website, linked below).
My point is this, the best time to do something is now. Don't wait for retirement (fixed income) or some other special circumstance (lottery win) or space and time (a 40'x60' empty basement). "Negotiate" with your spouse space for your hobby (a model railroad) that will make you happy and content now, and just do it.
Do it now, not in 6 months, because you could have a brain aneurysm two weeks from now and depart this realm without having done, or at least started, what your heart really wanted.
Besides, once your are gone, none of it really matters. Life continues on here regardless, and living remain behind to cope with the loss, while the departed do not care (they shouldn't and ultimately can't be bothered one way or the other).
Oh, and who cares if you are going to move out of the place you are living in, in X years. Ultimately just leave your built layout behind, and let the next owner deal with. People demolish and rebuild their homes all the time. Yes, I am oversimplifying things, but it really is that simple.
Lastly, do NOT let things take their course on their own as they will never transpire the way you want them to. The force governing this galaxy (or this universe) is based on intent. You project your intent out and it comes back to you amplified. The stronger the intent, the stronger the outcome in your favour.
Would you rather say that you started something and perhaps never finished; or never started anything at all because you waited for __________ (fill in any number of reasons, excuses, etc. that we humans like to make up).