How did Alice presented herself to the Caterpillar?

From the text:

The Caterpillar and Alice looked at each other for some time in silence: at last the Caterpillar took the hookah out of its mouth, and addressed her in a languid, sleepy voice.

`Who are YOU?' said the Caterpillar.

This was not an encouraging opening for a conversation. Alice replied, rather shyly, `I--I hardly know, sir, just at present-- at least I know who I WAS when I got up this morning, but I think I must have been changed several times since then.'

`What do you mean by that?' said the Caterpillar sternly. `Explain yourself!'

`I can't explain MYSELF, I'm afraid, sir' said Alice, `because I'm not myself, you see.'

`I don't see,' said the Caterpillar.

`I'm afraid I can't put it more clearly,' Alice replied very politely, `for I can't understand it myself to begin with; and being so many different sizes in a day is very confusing.'