If I register a business name and I don’t do the business or I take time to start the business, is that wrong?
Is it illegal, if I registar a business name now and start the real business after couple of years?
no, just be prepared to pay to register the business every year.
Where did your register it? state, county, etc? Assumed name or Doing Business As registrations typically do not expire. Call the agency you registered with and find out.