When Should X-ray Be Taken After The Fall?

HI I'M A 45 YR OLD FEMALE TODAY I FALL DOWN OUTSIDE VERY SLIPPERY, ICY STEPS AN I LANDED ON MY LEFT ELBOW REALLY HARD I'M ABLE TO MOVE IT BUT I NOTICE THERE IS A VERY SMALL DENT IN THE ELBOW NO BRUISING YET JUST WOULD LIKE TO KNOW IF I SHOULD HAVE A X-RAY DONE, I DID APPLY ICE.