YOU SAID:
The youngest is a big
INTO JAPANESE
最年少は大きいです
BACK INTO ENGLISH
The youngest is big
INTO JAPANESE
一番若いが大きい
BACK INTO ENGLISH
The youngest is the biggest
INTO JAPANESE
一番若いのが一番大きい
BACK INTO ENGLISH
The youngest is the biggest
That didn't even make that much sense in English.