As someone with a great deal of experience in this subject... (as an expert with years of experience in the field of undergraduate courses exhibiting incomplete, withdrawal, or failure marks, I can assure you, you have nothing to worry about.
For enrolling in a course, the act of registering is what determines whether or not course credit is granted. The only exception to this is if one is withdrawn from the course, perhaps(?) -- I wouldn't know, as at some point I seemed to even sink to the level of being too pathetic to bother taking the 2 minutes to withdraw from the courses I knew I was guaranteed to fail in by junior year.
All I know is, I have a 1.34 GPA, and as long as I get that up to a 1.5 or greater, I'm set. I have way more course credit than is necessary to graduate with, and perhaps only a couple of courses I haven't taken that are required to be taken (such requirements to graduate do require meeting a C- or better, at least at my school).
Rest assured: I am "a full time student" even though I took 3 courses and am about to withdraw from all three. Knowing this does not affect the student loan deferment date, and that W's do not affect my GPA, I am mainly doing it as I needed to extend my father's health insurance to me, and this makes that possible. Added perk: student loans are deferred an extra year (I still plan on finishing, by going next semester for real).
Of course, it's not ideal... and, most "incompletes" turn to F's largely because the student builds up the importance of the paper's significance to irrational levels-- so much so it is overwhelming to him/her and it is never completed due to the anxiety that results.
moral of story: don't be me, but, you're fine