There are a few ways to ballpark your computers age. If you haven't formatted your pc ever then the windows install date will tell you the first time it was installed. Go to your command prompt by typing cmd in search then type systeminfo. The other way is if you have a sticker on your pc that is the date of manufacture. If there isn't a date use the serial number and contact the manufacturer. The last way would be to check your bios in the search bar type system information and choose system information in the results. The bios version/date should be found here.