Not really. The above sentence is predicative (telling a fact: that the house IS pretty).
Your sentence on the other hand, is attributive, attaching the adjective to the noun to describe it. That would be rather translated as بيتي الجميل (notice how the adjective gets AL to be defined, because the first word is defined already with the possessive article ي attached to it)
It happens with me with other languages on Duolingo. I think it all comes down to 2 factors:
1. How much we accustomed to the sounds of the language we are learning and the number of vocabulary in our memory's bank. This helps the brain to correlate to the closest match to understand the sentence.
2. Obviously, the sound system. Sometimes even having the volume up makes the sound bad so I would turn the volume down and listen carefully.
In real life, it's normal to mishear the speaker even if you two are speaking the same native language.
My pretty house = بيتي الجميل (baytiya al-jameel).
My house is pretty = بيتي جميل (baytiya jameel).
The presence and absence of the definite article (AL) with the adjective makes all the difference here. With the definite article, the adjectives here becomes defined and since it is defined then it must be an attachable (attributive) adjective to the word before it بيتي because attributive adjectives in Arabic follow the noun in gender, number and most importantly, definition. The word بيتي (my house) is considered defined by the virtue of the possessive suffix here ـي (my).
On the other hand, if there is no definite article, then we can tell that this adjective is a predicative, because the predicative (the information we are telling in the sentence) is mostly always indefinite in Arabic. Thus بيتي جميل must be (my house IS pretty).