Share 'So many chords, and so many variations for the same song, how do ya know which is best for you?'

I am learning "Wildwood flower" and my teacher showed me how to use a capo and use the chords G,D, and C..When I got home I realized that there seemed to be no chord for the really high part and I noticed the D7 seemed suitable, but then the other chords didn't seem to fit. I looked online and the chords D,A7, G and D7 were suggested and so I tried this and liked it better.  What do you do, when…