I'm trying to come off about a decade of poor habits myself, due to a number of factors which are undoubtedly my responsibility but which it's not clear whether I could have realistically avoided. I've had some minor successes but have never really stabilized so far, including in all the little things like the above. I don't usually see this case handled clearly in the “it's okay to be a late bloomer!” inspiration crowd. (More personally, it doesn't help that the things I most want to do in life probably require being exceptional in specific ways that I'm not sure I can predict in advance and not just “successful” in a generic sort of way, and beyond a certain limited extent, I don't consider the wanting-what-I-have approach to be a viable one (except insofar as having that attitude on the face of things may make it more likely to reach my original desires anyway).)
I'm trying to convince myself to try anyway and it's hellishly difficult.