Pride is a very strange word in the English language; it's used in two very different ways, corresponding roughly to egotism and confidence. That is, roughly, to hubris and humility.
The sin of pride is placing more than due importance upon the self; the virtue of pride (as the term is unfortunately often used) is either placing the correct amount of importance upon the self or forgetting the self enough to judge one's abilities accurately.
What's so weird about this is that pride is the deadliest of the sins, but an accurate appraisal of the self is required for a self to accomplish anything. What brings this to mind is that Larry Wall is famous for the quote, "Three great virtues of programming are laziness, impatience, and hubris." He explains himself quite well in all three, but the relevant one to the moment is hubris: Wall explains that hubris is necessary because a programmer has to think enough of themselves to believe that they can actually solve the problem that they're setting out to. The problems we programmers solve are often difficult and complex, and it's often difficult to believe that they're actually solvable. (The same holds for every type of creative work.)
But this is just self-forgetfulness — forgetting about the self long enough to work on other things.
I'm facing the same thing as I work on my first spec script. I've felt the same thing in all sorts of other endeavors, though — it's difficult to believe that uncommon things are reachable by mere mortals. The weird thing is that no matter how many times you does this — do something which is only done by the chosen ones — it never makes you feel any different the next time. You'd think that after a while the possible would actually look like it.