That's the major 4th going in to the minor 4th, it's not just any major going in to minor chord progression. Minor Chord 4s always sound beautiful (but sad!) in this case we're in the key of A and the 4th is D and The D to Dm is quite commonly used in rock and pop music everywhere!
Wow, you've make it very well, you have my respect for 2 reasons: first because you interpret de instruments and the voice in the piano (really good and complete) and second because you like green day :D like
Dude you're awesome, it's lovely the way you play this song. This song it's particulary one of my favourites of Green Days and in piano, uff you make me shake boy. Super cool 8)
