i think "grosse" means "heavy" in this sentence not "big" , "la fille grande" is a wrong answer here
I'm not sure I get what you want to say. But here “big” is either « grosse », or « grande » if you speek figuratively. In english, if you say (affectionately) “big boy”, in french it's « grand garçon ».
can 'gros' and 'grand' be used interchangeably in french?
If there had been a choice of La grande fille, would that have been a correct solution as well?
is grande/grosse for feminine ?