If you've the time begin studying the Algebra II stuff at once on your own, doing exercises and problems as the ones you did the first time you took it. At the very
same time check what kind of basis is required from you to fully understand the course and, in case of need, try to fulfill the gaps.
Finally, think of the staggering amount of not-so-brilliant-to-say-the-least-if-you-don't-mind-my-saying-so people that has taken Algebra II and succeeded at
it (perhaps you know some of them!) and then think optimistically that if they made it then you're going to kick ass this time in this course.
At any rate, the best of lucks to you!