This quote comes from the very end of Chapter One. It is important to examine quotes in context as they help us to understand their meaning and import. If we look at how Ponyboy uses this quote, he is talking about his relationship with his elder brother, Darry, and how he is trying to convince himself that he doesn't care about their poor relationship. Have a look at the few lines before:
Darry doesn't love anyone or anything, except maybe Soda. I don't hardly think of him as being human. I don't care, I lied to myself. I don't care about him either. Soda's enough, and I'd have him until I got out of school. I don't care about Darry. But I was lying and I knew it. I lie to myself all the time. But I never believe me.
If we examine this quote carefully we can see that Ponyboy's habit of lying to himself "all the time" is something that he does in response to bad situations and unpleasant circumstances. In particular, here he is lying to himself because it is easier to try and convince himself that he doesn't care about Darry than facing the truth and trying to do something about it. Ponyboy admits that this lying is a strategy to make his life easier but that also it doesn't work. This is the meaning of the quote you have selected.
He lies to him about everything and he also mentioned he never believes the lie anyways.