I'm not sure how your school works, but where I go the math levels go Algebra 1, Geometry, Algebra 2, Trigonometry, Pre-Calc.
Are you saying you are going to Algebra 1? If so, you should be just fine as long as you did okay in pre-algebra during your middleschool days.
If you are going to Algebra 2, you need to be certain you know all the other Algebra by heart, or that class will eat you alive.