Agree with Mike and Obes. By modern gaming standards 15GB is not very large. It is not unusual to see 50GB and above. I think GTA V is 50.
Also gaming is like any other hobby. If you don't do the basics to stay up to date you will have a few hurdles to overcome. Think of storing a for wheeler for an extended period. Gas goes bad, lines can crack, blah, blah.
Pick a few games on Steam (or whatever), install them, and let Steam keep them auto updated. Updating video drivers is on you, however AMD and Nvidia both have utilities that help keep you up to date.
I hear that the ONLY FPS to play is BF4...