Just starting lessons with an acoustic guitar and have reached the "spider legs warm-up" lesson. I find that my ring, middle, and index fingers do not space properly on the first three frets. They pull together, especially when attempting to put the right pressure point on the string so that the adjacent string is not "contaminated". I can separate and hold them with my right hand but even then the pressure points on the tips of the fingers are thrown off. Are there any exercises for stretching/strengthening fingers or is It that I just may be physically/structurally unable to play the guitar and have to give-up my goal. By the way, I am a very active senior citizen in superior condition, but maybe not for the guitar.