I caught my PB at 7.73 this spring and my digital was not working. Had an old manual from boy scouts 45 years ago. Then ran it to the marina in a bucket and got an official weight. The old manual had it at 7 3/4. I was surprised how accurate it was. Fish was fine as I was fishing off the dock and just put it face first into the bucket and ran like hell.

Way too skinny for 12

If you don't have a way to measure cut some line and get length and girth measurements and you'll get an approximate weight using a chart...

https://tpwd.texas.gov/fishboat/fish/recreational/catchrelease/bass_length_weight.phtml

Nice fish.