Wanting to be healthy

It's so hard for me to be healthy with what I've been given. In order to eat healthy, you have to go against what society says is a "portion", and what they say you need to have on your plate...a huge serving of meat, and lots of starchy foods, and then dessert afterwards. It's especially hard now that Mark has a job, and we can afford to go out to eat, sometimes two or more times a week. And you always feel like you have to eat what was put on your plate, because you paid for it. A lot of the times, Mark and I will share a plate, and we notice that it's more than enough. It's as if Americans eat a double portion of everything!
I thought I was healthy. I choose water over other drinks most of the time. I only eat white meat. I don't pig out on chips all afternoon in front of the television. But I realize that I'm not really all that healthy; I splurge a lot, and eat things that aren't that great for me. Sugar is one of my weaknesses. And a lot of the time, I eat more than I really need. I don't eat vegetables as often as I should. I find myself choosing fatty foods and carbs- we eat a lot of pizza.
When I went got my blood work done at the doctor, my good cholesterol (HDL) was low. They told me to eat better and to exercise. I have been doing that, haven't I? It must be something else, I thought to myself. Maybe a side effect of a medication.
I realize, however, that I do not lead a very active life all of the time. Sure, there are times when I ride my bike, go on walks, and maybe once or twice a week, I really get my heart rate up with a work out video. But is this enough? Does it compensate for all of this sitting around? I wish I had a treadmill by my computer, so that at this very moment, I could be getting some healthy exercise.
I know some of you may be thinking, "you're so skinny, why do you need to worry about stuff like this"? I worry about this because my health is at stake, no matter how good I look on the outside. I don't want my body to learn bad habits, to build up mechanisms that will hurt me later on. It's not just about the weight; it's about staying healthy. And it's crazy how many bad things you can prevent just by eating healthy and exercising! Just about every disease can either be prevented or made better by living a healthier lifestyle.
So even though society tries to tell me that the more cookies I eat and the more time I spend on the computer the better, I think otherwise. I need to do something for my health, and I want to start now.