I don't know whether you're interested, but if you click
here and scroll down to the heading 'Earliest Text', you will find a poem written in Old English during the 600s...ie - apparently - before any of the above words.
It contains several words which are easily recognisable to us today such as weard meaning guardian (the modern equivalent would be ward)...weorc for work...wundra for wonders and so on.
All-in-all, I'd guess that it is virtually impossible to state categorically which English word is the oldest!