Is this a yellow stainer?

Found in Victoria Australia, on grass but near woodchips in a disturbed environment, near a road. I thought it might be a field mushroom but the stem went a little yellow when I cut it. However, after 1/2 hour the cap hasn't gone yellow after I tore a chunk of that.

So I wondered what this was, and is it Agaricus xanthodermus, or some other kind of Agaricus?

https://preview.redd.it/cg5h8omoul5h1.png?width=510&format=png&auto=webp&s=3f3e0aacc1c8abf4aa0100b7b5bb787928639d9a

https://preview.redd.it/tuxessmoul5h1.png?width=532&format=png&auto=webp&s=9aca20b8c9dc19cdbbbe5ae35a04d2e2c32e4a19

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u/JasTWot — 3 months ago