מחשבה מועלת אפילו לדברי תורה - Thinking about doing something is enough to keep you from doing it, even when it's Torah. Sanhedrin 26b
Rashi: This means that if someone says he will learn such and such number of pages, certainly it will be impossible for him.
The Noam Elimelech (פרשת שמות) tells us something amazing: A Tzaddik when he speaks the words of The Creator of the World it is utterly impossible that those words will not break the heart of all who hear them.
This he tells us specifically in relation to Mosheh and Paroah. HaShem tells Mosheh to tell Paroah to let his people go, but God says he will harden Paroah's heart. The Noam Elimelech says, it's impossible that Paroah's heart could withstand the words of God. Instead he explains, in line with the teaching above from Sanhedrin, that God was telling Mosheh to fully intend to break Paroah's heart with God's words, and this intention of Mosheh's, that Paroah's heart would break, was enough to ensure that it could not be broken.
We can take two things away from this: First, the obvious lesson from Sanhedrin--Don't worry about planning how much Torah you are going to learn, just start learning in whatever time is available to you. Which includes the more general expression: Say a little and do a lot. (אמור מעת ועשה הרבה)
Secondly, as long as we can read the words of HaShem, as recorded in the Torah, and they don't utterly shatter our heart, we have a ways to go on the journey to being Tzaddikim.
Of course we can't plan to shatter our hearts, or it would [chas v'shalom] be impossible.