D’Ooge says that the most important words are the first and the last. An adjective is considered less emphatic placed after the noun (casa mea) if these words are the last two words in a sentence should the adjective be put before the noun if it is desired to keep the adjective less emphatic, due to the fact that the last word does carry a certain amount of emphasis?
It’s not really the first or last word that receives the emphasis–it’s the grammatical unit. So in your example the whole noun phrase casa mea would be placed as the last element in the sentence, with mea following casa, unless you want to emphasize mea by inverting the neutral N Adj word order within the noun phrase. By the way, in Latin casa means “hut”, not “house”, if that’s what you intended.