^^If you have an Iranian passport then your trip must have been before the new laws. The new laws prohibit you from entering the US without an American visa.
You guys need to read the rules of foreign travel advice in your country and/or the American embassy's site in your country:
Foreign travel advice:
Visa Waiver Programme (VWP)
Most passport holders can get an Electronic System for Travel Authorisation (ESTA) through the Visa Waiver Programme, which allows travel to the US for up to 90 days. The types of journey allowed under the VWP include tourism, certain types of business visit and transit to another country.
You’ll generally qualify to enter the USA using the VWP if your British passport:
and you:
- have received authorisation from the Electronic System for Travel Authorisation (ESTA)
- haven’t been arrested for certain crimes, even if a criminal conviction didn’t result
- aren’t a dual national of Iran, Iraq, Sudan or Syria
- haven’t travelled to Libya, Iran, Iraq, Somalia, Sudan, Syria or Yemen since March 2011
- can show that you have enough funds available on arrival to support yourself during your stay, even if you’re staying with family and friends
Certain exemptions apply on a case-by-case basis to those who have travelled to Iran, Iraq, Sudan, Syria, Libya, Somalia or Yemen since March 2011. For more information see the
website of the US Customs and Border Protection Agency or contact the nearest US Embassy or Consulate.
Source:
https://www.gov.uk/foreign-travel-advice/usa/entry-requirements
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US customs and border protection:
IMPORTANT NOTICE!
Travelers in the following categories are no longer eligible to travel or be admitted to the United States under the Visa Waiver Program (VWP):
- Nationals of VWP countries who have traveled to or been present in Iran, Iraq, Sudan, Syria, Libya, Somalia and Yemen on or after March 1, 2011 (with limited exceptions for travel for diplomatic or military purposes in the service of a VWP country).
- Nationals of VWP countries who are also nationals of Iran, Iraq, Sudan, or Syria.
Source:
https://www.cbp.gov/travel/international-visitors/visa-waiver-program