i can't think of any tune with over 15 chords on it especially not in a rock / pop genre....
but i digress.
i wouldn't start with the "fiddly" parts of songs 1st no matter how much you want to play that intro riff to wanted or play the solo to prayer.
learn all the major and minor chords and start playing the chords to the songs. once you get your rythmn and chord changes sorted you're fingers will be much stronger and your hand coordination will be better so moving onto riffs and solos will be easier.
i'd learn some theory too. i knew a shitload of theory in high school because of music classes and to be honest now i couldn't name you the notes in a D major scale without some serious effort
