Hi Michelle,
Click on Setup and go to Fiscal Years. There is an option there to change a Year-end. You are only allowed to shorten fiscal years (as no year can be more than 365 days), but if your start date was correct then it may let you change to December 31st. If not then you will need to Add the next fiscal year, then shorten that fiscal year so that it is only one day (December 31st) and then your years will be set to begin and end properly.
Alternatively you may want to look at starting your file over again if you haven't done much other setup yet.
