And it should be an, not a.
Incorrect.
“H” is a peculiar consonant. The a/an rule is simply stated as to use “an” in front of words beginning with vowels. However, the more complete rule includes and words beginning with vowel sounds.... Works beginning with “hi” are in this category. Example... A hat but An historic (historical) event.
I see an high mountain? Somehow that doesn’t sound right.
I see an high mountain? Somehow that doesn’t sound right.