reset($array)
will move the internal array pointer to the first element and return that element as well.
Note that "the first element" not necessarily means the element with index 0. It means the first element that got added to the array:
$array[1] = "foo";
$array[0] = "bar";
$first = reset($array); // foo
You might want to sort the array before fetching the "first" element.