Trust me on this, every professional, when they are just learning have the same fear of leaving the comfort zone of what ever note or riff that they are able to do well. The old adage that "If it ain't broke - don't fix it" does not apply to musicians. Our adage should read "If it ain't broke - break it, again and again". This warm up should be played with a triplet feel and each new triplet should be fingered with your index. Start on the first fret then run the warm up, advance one fret and run it again. As always be sure to use a metronome and start slowly; in the beginning the "real" music you play is called patience.

Best of luck!