Geesh!

I'm 5' 11" too. But definitely not 133 lbs and definitely not 12.8% body fat. Hopefully I can use this as a challenge to get fitter and less weight by the time my GP sends me off for a Dexa Scan. Probably 3 years or so from now.

I'll be extremely happy if I can get down to 151 lbs and satisfied at just 160 - 165 lbs. I doubt I could ever get anywhere near to a elite body fat 12.8%

I'd be curious to know if your doctor has given you any cautions about it being that low. Though it is a common level for the very athletic.