Je suis'ai 44 ans. J'ai 44 ans.

In French as in all romance languages, you "have" your age, you "are" not it

J’habite àen Virginiae, aux États-Unis. J’habite en Virginie, aux États-Unis.

"j'habite à Virginia" would refer to a city called "Virginia" I suppose you're talking from the State though, so it would be "Virginie" in French Feminine countries/States or countries/States starting with a vowel (regardless of gender) = en => EN Virginie

J’ai trois chats : Marjorie, Georgia, et Coco. J’ai trois chats : Marjorie, Georgia, et Coco.

You may also say "j'ai trois chaTTES", if they all are females

Je 'apprends le française (vraiment lentement). J'apprends le français (vraiment lentement).

je+vowel => j'