"Does it matter if it is changed?
Does changing the Key also change the song?"

No & Yes.

No - all keys in 'modern 12 tone chromatic tempered tuning' are equivalent. Totally. Absolutely. The 'old idea' that there WAS a difference only applied when 'just tuning' (in Western European Society) or other tempermanents in other cultures were used. Basically the Piano Accordion killed most of those.... (I'm a Piano Accordion player!)


Yes - the key is important if using another jey would not fit the vocal range of the singer or the instrument - or if a particular key is more difficult for a particular instrument to play in.


End of Story.

The rest is just personal opinion... (often by the musically untrained) :-)

:-P