You can do either as one is not a prerequisite for the other. Many schools do Geometry before Algebra 2. You may choose to go that route to be consistent with what is happening in schools. Other people choose to continue on to Algebra 2 first to do it while algebra skills are still fresh. We have a slight preference for Geometry first as there are generally more Geometry questions than Algebra 2 questions on standardized tests like the ACT/SAT.