Thanks for reading this. I am going to make this simple. Here is the situation. Last Thursday, I encountered a professor that I know personally. He asked me to join his class for the coming autumn. I did not reply his request immediately. That night, I looked up informations of that class. It fits my time table. And this is where the situation gets confusing. I have already registered the following classes for the coming autumn. They are TOPOLOGY, MATHEMATICAL ANALYSIS I, ABSTRACT ALGEBRA, MATHEMATICAL ECONOMICS, PROBABILITY, and NUMERICAL ANALYSIS which already maxed out my normal credits maxium per semester. However, the class,PROBLEM SOLVING FOR MATHS COMPETITION, he asked me to join does not overlap with any other classes. I am going to graduate in spring 07. I am going to apply for postgraduate school and majoring in Operation Research/Financial Mathematics. These are professional degree and require applicant to have work experience and recommandations. The professor is very famous in pure maths field. His recommandation would be very helpful for my postgraduate application. Though, I already have 18 credits of workload (less important), and schedule of that class will greatly decrease the possiblility of getting internship(important). I am just 19 years old and I have not worked in any financial industry at all (fair amount of experiences in food industries and salesman). Of course, it is not guaranteed that I am going to get intership/his recommandation. What should I choose? My primary decision would be to join his class. However, I am in the situation therefore i might not see things clearly. Thanks for reading this again. Any thought would be appreciated.