Many of my family members have built their own homes, I have not (I do not swing a hammer......it's just not a skill I have ).
Four years ago, I built a home through a general construction company- I chose a floor plan, chose my lot, chose my upgrades and moved in 6 months later.
At the same time, a close family member had bought a lot and began building his house........he still hasn't moved in. He and his wife have devoted four years to the home, worked on it constantly, had additional family help and hired subs for some parts of it.
His home was recently appraised at a value nearly identical to what my own home cost me (within $5k).......but that was 4 years ago. Meanwhile, my home value has skyrocketed well beyond what I paid for it (and I've been living in it all this time).
Granted, 4 years is an unusually long time to have a house built, but over a year is common (plenty of people run into the two year mark before they can move in).
In addition, these days, mortgage companies and insurers are shying away from individual home builders, so you may have some challenges there.
It sounds like a wonderful idea, and many people can pull it off just fine and be very happy with the process and the end result, but it can also be fraught with difficulties......I'd map it all out on paper in great detail before I'd even buy the lot.
Best of luck with your decision .