Can I download games on a ios 7.1.2?
ALWAYS, ALWAYS, ALWAYS do a complete backup of everything that is important to you before doing any system updates on your phone.
I backup to the cloud and then backup to my computer. That way there are two full backups of the things I need backed up, text, email, apps, etc. That way if anything goes wrong, I can factory reset, then apply the update,then restore things to the updated OS.