Do you mean build it yourself, or have one built? I did about 90% of the work on our house single-handed, but it's smaller than what you have in mind. To do it right, there's a lot to consider. Do you have land yet? I watched our property for a year to see where the sun rose and set. I carefully oriented the house on the property to best capture the views, and for energy efficiency. I looked over thousands of existing plans, and went on sites such as Houzz to get ideas and bounce ideas off of other people. I went on energy efficiency sites such as Green Building Advisor to learn about that.
I built our house out of ICF, and had 18" of cellulose blown into the attic. It's incredibly energy efficient, solid, and quiet. Due to our sloping land, I built on a full walk-out basement. Since it's insulated by virtue of the ICF, it is usable year-round without HVAC. On flatter ground, I would build on a crawl space. The suspended floor is easier on your feet and back, and it gives you access to utilities under the floor. In FL, everything was on a slab, and I swore I'd never live on a slab again.
The floor plan is crucial to get a house that flows well. We've all been in houses that just don't work well, even if you can't quite figure out what's wrong. In our last house, the so-called dining room had five openings into other rooms, so if you put a table in it, it just made it harder to get to other rooms. The back porch faced west (in FL), so much of the year, it was too hot to use. The master bedroom only had one window. You should try to have windows on two walls of every room, if possible. The kitchen in that house was a tiny disaster, especially as we both like to cook. It had five drawers; our kitchen here has 33 drawers. For some reason, they dropped the ceiling in the kitchen. Why lower the ceiling in a room with heat and steam?!? It was a typical tract home, built by the millions to a price point, with little thought as to what they are like to live in.
I'm not telling you all of this to discourage you; just the opposite. If you can afford to build a house, you might as well make it a good one. Otherwise, just buy an existing home.