For example, I'm in an advanced math class where I can actually earn college credit for next year's university.
Literal
For-example I [topic-は], next-year enter-school university [of-の] credits [subject-が] actually can-get math [of-の] upper class [in-に] am.
A dense high-school-student sentence explaining an advanced placement situation. 実際に ('actually, in practice') emphasizes that the credit is real, not notional. もらえる is the potential of もらう ('to receive'). The whole modifier ~もらえる数学の上級クラス is a long relative clause modifying クラス.