Here's a link from microsoft on your question. http://windows.microsoft.com/en-us/windows7/products/system-requirements
Windows XP debuted in 2001. Microsoft Discontinued the OEM's for Windows XP in 2008. So at a glance without your system specs. I'd say your computer is at least 5 years old. Rather or not you can install it "I'd say you probably shouldn't unless you meet the recommended(not required) system requirements.
I agree with what A.Karantze said and make sure before you do this that you backup all of your important documents, pictures and music before wiping your system because once you wipe your system you can't get anything back. I hope this helps you with your decision