Sylivia

I booked my e- ticket two weeks ago..
However one of the my firstname was misspelled..
My travel agency called usairways, and then she told me "You don't have any problem because they already changed my name..
When I checked my book in web-site, my name is still wrong, I called usairways, they told me Even though your name is misspelled, we already set. You will bring just vaild I.D...

I am really worried about that....
What should I do?

*The flight is domestic flight PHL->SFO