score:4
There are no issues with changing your plans, as long as the change is an honest change.
If your change leads the Customs and Border Patrol staff to believe that your visa was obtained via fraud, then they can take action including denying you entry to the country and invalidating your visa.
Simple changing your holiday plans would not trigger such a determination. However if (for example) you obtained your visa on the premise of coming to the US for a holiday, but instead changed your plans to enter the country to look for work, then you might have an issue. As that's not what's happened here, you'll be fine!