Avery there is a cautionary saying about building your own boat. It is not kind.
"Fools build boats for wise men to sail"
Expect your FIRST boat build to take much longer than you think.
Here is a good example and also an excellent record of a build of a 44 ft Roberts in steel. CLICKY
It is also worth noting that they had a scare on their first offshore sail and seem to have given up on the idea.
As a full time liveaboard myself I would make a lightweight 44 footer about the max you would want and something around 38 to 40 ft ideal. If you want a steel boat then look at the French sites as they build a variety of steel boats, not pretty but good cruising boats. I would buy and not build at your age. There are too many sad stories of people not getting to enjoy the fruits of their labours.