Ready, set, go?

Well...I'm signed up.  Full load.  12hours.  And n-er-v-o-u-s.  What if my note taking skills have gotten bad?  I've always been really tough on myself and gotten good grades.  I pay attention.  I sit in the front.  I listen to the instructor.  Now I'm worried that it will go too fast.  That I won't understand, that I won't be able to keep up.  I feel like I'm psyching myself out and that everything will be fine...but what if it won't?