The decisive point in the turn to Judaism is not the initial awakening, which can be seen merely as a response to a call.
It is, rather, the inward affirmation of "we shall do and we shall obey"—the decision to address one's life to the realization of this commitment—that makes the turn real.
Rather than waiting for an opportune time to make the change all at once—something that may never come along—it is better to change one's life gradually, by stages, according to one's inner capacity and outward circumstances.
But this does not lessen the importance of making a firm decision at the outset.
There is a crucial moment in which one "receives the Torah," with all its contents, both general and specific.
It is then that one sets out on the path, toward the realization of one's resolve.
Some are able to achieve this relatively easily, passing as if by magic from one world to the other, and encountering few obstacles or difficulties.
But for most it is a complex, long drawn-out process, fraught with tribulations.
And again the question that must be asked is not, "Must I do all or nothing?" but rather, "What beginning can I make that will facilitate eventually reaching the goal of doing all?"
–Rabbi Adin Steinsaltz
From Teshuvah, p.22, by Rabbi Adin Steinsaltz