Happy Ram Navmi to all.
Why is there a confusion between dates?
Because the Indian/Hindu calendar is based on the moon phase (Lunisolar calendar) as compared to the English calendar which is based on Solar phase (Solar calendar). So, the timings also are different.
Sometimes, a day in Hindu calendar might lie half on one date & half on another in English calendar. So, then it depends on the people/local government to decide on which English calendar date to celebrate the festival on that day.
I hope it is clear.
(Eg. You might have heard your mother say, Poornima/Amavasya starts at 8 AM/PM or any other time).