The speaker is still in the process of convincing himself, even to the point of self-delusion. He tries to tell himself that, should this road proves not the right one, he will have the chance to go back to take the other road. Yet, in a road of complete honesty, he knows that life will probably not allow him the choice to return, even if he should wish to. He has transitioned to the point where he realizes that his youth is past and he must take up the responsility and reality of adulthood.