I guess I would ask the same question as above -
You must own Powertracks or Realband .. why are you doing projects in Audacity?

Easy fix, even after the fact, in either of the above programs, just grab it and slide it.
Or cut a small sliver before the playing starts and choose to 'close the gap'.

I've never tried to adjust the recording settings (or do very much editing) in Audacity, it seems untuitive to me, especially the effects and edit areas.

Laying on the beat is exactly what you want in some some songs.. and in some you may want the guitar pushing the beat .. it all depends on the song. If it is late and you don't want it late, just import the wav files from audacity into RB or PT and you can adjust any of it very easily.

Make your sound your own!
.. I do not work here, but the benefits are still awesome