I personally think Anastasia is “pretty.” I mean, look at her.
What makes her “ugly” is her un-dainty nose and her laugh-lines. Well, and that God-awful hair-do.
But look at her here:
Besides that, you don’t base your cosplays around how pretty or ugly you are in comparison to the character. Same with race, weight, height, ect. Your physical traits should not stop you from enjoying yourself.