WhitBri

I can't say that I've ever had this happen to me, but I know I take extra precaution to silence my bow. When I say silent I mean silent. Doesn't matter what bow you shoot you can get it to be quiet. One easy fix is always put on the string silencers the rubber stringy looking ones work fine like a buck to buy but they work wonders, also tons of other products too. Quiet is way more important then speed in my book, I shoot a mathews now that's both fast and quiet, but before I switched I use to shoot an old bear bow with aluminum arrows at a max of 190 fps, but couldn't hear it at 10 feet away so a deer never jumped the string.
Only my opinion but most of the time lack attention to detail is the cause of a deer jumping a string, especially at 20 yards. We owe it to the deer to think about every aspect of the shot especially the noise of our bows.

MOTOWNHONKEY

Perhaps since you are a new hunter you punched the trigger and shot over the deers back. Maybe it was just a miss. We all have done it. The last thing that I think on my check list before shooting a deer is Slowly squeeze the trigger.