You are right, but in German you also have to look at the gender of the noun:
So basically it's all depending on the article used: DER/DIE/DAS
DER and DAS use "Mein"
DIE uses "Meine"
DAS Haus -> Mein Haus
BUT: DIE Häuser (plural) -> Meine Häuser
Another one: DIE Frau -> Meine Frau / DIE Frauen (plural) -> Meine Frauen
The dress translates "Das Kleid" in German , but it asks for the plural "Die Kleider" and therefore you need to use "Meine"