Using an inheritance to buy, and probably completely pay for, your housing is a good plan. Is your education already covered though? Compare interest rates between student loans and construction loans. Whichever is lower (Student loans probably) borrow there.
It sounds like your money is well invested. I would just let it ride for the time being.
However, I would hold off in building/buying a house right after graduating college. You really don't want to tie yourself down to any one location and not having a house means that you can follow good job opportunities.
Once you find a job you like in a location you like, then get your house.
However, if you consider that you have $200,000 in the bank right now, that is an incredible jump on retirement.
I wouldn't spend it on a house right after graduating college because if you're like most recent grads, you'll move around a lot as you begin your career. I'd hold off & wait until you're sure you'll be in one location for 5 years or more.
don't be in such a rush to part with the money---you're planning on being around another for another 60 or 70 years & you have nice little cushion there to start you out.
What do you intend to do with your 'first house'? If you are building with the view of living in it, that's the very safe option and will probably be the end of your entrepreneurial enterprises. A house that is a home doesn't earn you any more. You'd do far better to get a mortgage to build, and do something else with your capital, or buy to rent and to build up a portfolio of properties, if you want your wealth to grow.
The best advice for you is to learn the basics of investing. Start with a fundamentals book like "Investing For Dummies."
Don't buy a house, use the money for your retirement.
You are in great hands. Congrats man.
sounds like you are in good hands