At the risk of alienating some Facebook friends, my response is that this seems to me like a half-truth that mainly applies to middle and upper classes in the First World. What's written is largely true except, sometimes, the age part. I understand where this is coming from. The author is telling us to take responsibility for our own lives and not get bogged down on blaming others for the hole we find ourselves in. But the temptation is to turn it around and wash our hands of responsibility for others by saying that they are responsible for themselves..
What's missing in this inspirational message is that the choices we make before reaching the age of reason or after acquiring dementia could not be responsible choices. After that, the choice options available to many people are often very dependent upon where they were born, where in the world or city they live, whether they even have a job or schooling, the weather in a world of climate change. Choices available to child soldiers and girls sold off in arranged marriages are zero to none yet they are often held responsible and punished, or abandoned, as if they had freedom of choice. Adults and juveniles in families facing severe hunger and deprivation make choices under desperate conditions but often are still held equally accountable as their more privileged counterparts.
You are responsible for your choice only to the extent that the choice is understood and freely made with full knowledge. Such freedom and knowledge is on a sliding scale, not on an on/off switch. This is why politicians who preach simplistic, slogan-based responsibility with automatic, minimum, punitive sentences are so dangerous.
For all these reasons and more, I do not agree with the catchy slogan: you and only you are responsible for every decision and choice you make.
However, I also operate on the principle that I had better take responsibility for getting myself out of the hole I am in regardless of whose fault it is that I am in the hole.