No, she wore it last year too, the pictures are all on Getty. Search for 'Queen Elizabeth Chelsea' and you will see photos going back many years
--Previous Message-- : It is a first wearing of this brooch? : : --Previous Message-- : Yes, its lovely to see that brooch again, : and : even better not to have any 'hair nets' ! : : : : --Previous Message-- : The Queen visits Chelsea Flower Show wearing : her Chelsea brooch which was a gift to her. : No hat no scarf or net headwear. : : : : :