Why is it odd to give Alice the thimble as a prize?

It is odd to give Alice the thimble because it is HER thimble.

'Of course,' the Dodo replied very gravely. 'What else have you got in your pocket?' he went on, turning to Alice.
'Only a thimble,' said Alice sadly.
'Hand it over here,' said the Dodo.
Then they all crowded round her once more, while the Dodo solemnly presented the thimble, saying 'We beg your acceptance of this elegant thimble'; and, when it had finished this short speech, they all cheered.