I definitely wondered the same thing at first. I realised that a lot of it had to do with my motivation. Yeah, sure, I wanted to be thin, but it wasn't my priority. When I got finally sick and tired enough of being uncomfortable in my body, I felt motivated to do something about it once and for all. I was frustrated that I had let myself get to the point I was at and how allowed myself to remain at.
Then I got to thinking about it, and actually used that as my motivation. It was almost a year ago. I told myself to go ahead and get on the ball then, so that 3 months, 6 months, a year later, I wouldn't be sitting around saying, "Woulda, shoulda, coulda," you know? I felt like the sooner I got moving, the sooner I could see progress.
I saw an initial drop on the scale (water weight) but that kept me encouraged. Stuck to my plan, and in a couple weeks I could really feel a difference, and like a month in, I could really see a difference. I just kept thinking about how I didn't want to look back with regret for not continuing, so I kept it up. It's cool to look back almost a year later and say, "I'm glad I started and continued!" I promise you I'm not saying to myself, "Man, if only I had started sooner!"
I'm just glad that I did!