What does this mean?
Thou art woman, Thou art man, Thou art the lad and the maiden too. Thou art the old man tottering on his staff: Once born thou comest to be, thy face turned every way! A dark-blue moth art Thou, green [parrot] with red eyes. Pregnant with lightning—seasons, seas: Thyself beginningless, all things dost Thou pervade. From Thee, all worlds were born.

The Hindus believe that there is a Supreme spirit or Ultimate soul from which all the individual souls (Atman) of all living things belongs to and originates from.

Brahman is therefore the essence of life and the nucleus of the universe of living things. Brahman is the eternal nucleus of the universe and is all of us and we are all Brahman. This is why (as shown from the text), Brahman is a woman, man, child, maiden, old man moth and even a parrot. Brahman is beginningless and is the author of everything.