Years ago, I recall playing with a guy who had told me on the first tee that he shot 75 the day prior. He shot 87 that round with me. I was too inexperienced to understand how tough the game really is, or how quickly the scores can evaporate in just 24 hours. So I figured he was just trying to make himself feel good about his game.
I had a great round of 71 last season, then the next round out shot a very easy round of 85. LOL.... Thank goodness I didn't tell my playing partners during that latter round that I had just shot -1 on the same track three days earlier.
I've learned this much.... if you're really good, you usually don't have to make it a point to tell someone. They'll figure it out soon enough.
As someone mentioned, the Golf Gods are all ears. And they generally prefer humility over ego. LOL....