Register a company
The only type of company you are restricted from opening is an S-corporation. But you can feel free to open an LLC or a Corporation in the United States.
However, since you are not ready to engage in business, our advice would be to wait and register the company when you need one. There are some administrative expenses that are incurred every year by the American companies, such as annual report fees, registered agent fees, tax preparation fees. If you do not need the company, why pay these fees? And when you need one, the registration process is rather simple and can be done quickly.