Wildlife Spotting

Am I correct in thinking that there is one mushroom with brown gills with two with white gills growing right next to it? And that they look the same on top? If I had seen them individually I would have said the brown gilled one is an Agaricus species for sure, and that the white gilled ones were probably Leucoagaricus... But seeing as they appear to be the same species, I guess they must all be Agaricus, and the white gilled ones being less mature! It's just unusual for the mushrooms to get so big before the gills turn brown...