Good job so far!
Personally, I've always found it the easiest to stay on track for the first week or so because I'm feeling motivated. But I think it probably depends what you've been eating regularly, and what kind of cravings and physical addictions you might be working on overcoming.
For example, if you're used to eating a lot of sugar and you suddenly stop, your body may go into withdrawal. And if you're used to eating a lot of salt (chips, etc.) you might find less salty food "bland" for the first little while while your taste-buds adjust. Those kinds of things can definitely make it difficult to change your way of eating.
But like I said, for me, the difficulty comes later. This is because eventually it seems like a long, strenuous task to keep eating healthy, and eventually I tend to decide that I'd rather be fat than keep working so hard at being healthier. I think I've solved that problem for myself by rewarding myself for things I'm in better control of (specifically, logging calories), but only time will tell.