On the whole, the environment you were raised in and the experiences you had will shape the opportunities that are available to you and how well you can take advantage of them. Of course there are always exceptions, but these provide the general rule. Data over time consistently show that the best predictor of economic destiny is the background a person came from, though certainly there are many other factors in play.
While childhood can't predict economic destiny with 100% accuracy, it can predict economic outcome to a certain degree. Economic mobility (the ability to move between financial classes) is much more limited than what some believe. Many who are rich are born into wealth, and many who are poor are born into poverty.
Childhood most definitely does determine your economic destiny. The way you were raised and your surroundings during childhood play a big part in molding you for the future. Though one can change their opinions in adult years, the basic learning through childhood does remain with one as well as effect their economic destiny. This is why it is extremely important that we groom our youth with their future in mind.
To say that an individual has an "economic destiny" implies that a person is fated to achieve a certain economic status despite all other factors and events in his or her life. While an individual's childhood has a tremendous impact on morals, sense of self-worth, education and socialization skills it would be an oversimplification to say that it is solely responsible for an individual's economic status.