Let me start off by saying you should be proud. Very few people are willing to make a change in their life, and even fewer are willing to attempt something that isn't easy, even if the payoff is worth it. As for the people that make comments, ignore them, their like would heckle and cajole even a pro like Tyler or Lance if he rode in their neighborhood.
One question I would like to ask, is if you are getting enough rest between your excursions? Its great that you are motivated, but you need to treat this like a marathon and not a sprint. I'd love to tell you that things will go quickly, but thats not the truth, it will take time. Just make sure you are giving your body enough time to repair and adapt for your new level of exertion.
Keep up the great work!