Can i change my ein information?

I have just recently obtained my EIN through the IRS. i did this all over the phone. the nice lady i talked to said i need to have a date of incorporation. i said im not yet an llc and she said it is okay just give me a date that you should be incorporated by...i said well January the 1st....just because it was the start of a calendar year...she easily typed it in and i received my EIN. now i would like to become an llc earlier than the date i had told her due to the fact that i have the money early...would it be okay to form early if the irs has the info that i was going to do it on the 1st of January???