Most students in an introductory economics class have not had economics in HS. My S did not take AP Econ and did very well in his two college economics courses. Just stay on top of the work, attend class, do the readings and homework, study in advance for exams, see the professor or TAs with any questions, go to any review sessions if offered etc. and you should be fine. You will have to take many college classes that you have not taken in HS.