Is it reasonable for you to refuse to drive because you would rather walk or ride a bike because you want to be in good health and cars make you lazy and fat?
Doesn't matter if you are a guy or girl, your mother is more concerned about your safety and becoming more independent. You are absolutely correct in saying that riding a bike is good for you, but hey, my husband and I both have vehicles and we go for long walks and many of our friends also own vehicles and go bike riding to keep in shape, so what's YOUR problem? There is nothing wrong with riding your bike during the day, but at night you should be driving or if you mom needs a lift somewhere you should be willing to take her. Sorry, you're mom's right! You should be able to chew gum and talk at the same time (which means: drive and keep up the bike riding.)