You should not have any difficulty downgrading from Windows 8.1 to Windows 7.I have done it so many times on my old machine (it could not run windows 8 properly because of old hardware
, so returned to Windows 7
) but I suggest you that you should not be downgrading.
Initially it's metro interface may be a little confusing but Give Windows 8.1 some time and believe me You will really like it.I too bought a new laptop with pre-installed Windows 8 (updated to Windows 8.1) and i love it.
To get Windows 7 feel on your Windows 8.1, you can install Pokki and bypass it's Metro UI to log in directly to Desktop.
You may differ on my thoughts.
If you get any problem regarding that,please ask.I might help you.
have a good day !