... and, by the way, your question should be 'Is it correct?'.
'Correct' is an adjective, 'correctly' is an adverb. With the verb 'to be', we use adjectives, not adverbs. So you can say, for example:
A) Is this sentence correct?
or
B) Have I written this sentence correctly?
In A, the adjective 'correct' refers to the sentence. In B, the adverb 'correctly' refers to how you have written it.