<<Maybe that is Ann at Odd Down and the enumerator mis read her age. It does say N for bn in County>>
If we could decide that, we'd be on the way to sorting her out !!
In 1841 I believe ages were rounded down?
IF she died in 1847 at the age of 80, that means she was probably born 1767 as OP has said - but lots of people didn't know their exact age back then.
In 1841 she'd have been 74 or 75 depending on the date of her birthday and the date of the census (I can't remember that) .
I wonder if the enumerator wrote a 2 instead of a 7 ?? Though his 7s are rather different....probably wishful thinking