First time weight loss

I've never actually attempted to lose, when I was younger I no understanding of it. When I finally gained a little more control over my life it just wasn't convenient. I want to be done with making excuses now, but I'm afraid that this new found inspiration wont last long enough to have a good impact on me or my problem.

The size of what I eat isn't the problem. I rarely eat large portions, though I will admit that what I eat isn't healthy. Until about a month ago almost every meal was fried. I'm slowly but surely cutting fried food completely out of my diet but its more difficult than I expected.

I also don't have an uncontrollable sweet tooth. I've hated chocolate and most 'normal' candies since I was a child. I'd much prefer strawberries or an apple.

My issue is activity. I work in an office and am on my butt 8 hours a day there's no getting around that, but I'm so mentally exhausted by the end of the day that I can't pull myself off of the couch (or computer) when I get home.

I know I need to get up and start doing something, its not like I don't have what I need. There are walking trails near my house and I have a swimming pool, but I can't keep the motivation to do it! It doesn't help that my step mom (who I live with) is constantly picking at my weight and telling me what I should do...

I want to take my first real steps to a better me starting today...but I need help to make it a real life style change rather than something that fizzles out after a week or two.