Hello I am 45 and just started learning guitar. I am starting with GF1. I am on the first song, Walk Downtown been trying to learn it for a few days. I can make the chord changes and keep rhythm with the song. Having a problem with strumming the correct strings. It should be G,B,E but I sometimes strike D,G,B,E or B,E. Should I move onto to the second song in the lesson and keep practicing strumming or stay with this song and get strumming perfect?