Should I take a class that's not necessary?

Hi.

I’m currently attending a community college in California.
I fulfilled all IGETC requirements except for the critical thinking area.

I’m planning to take a critical thinking philosophy class in Spring 2018, and I’m currently taking Physical Science 2 class which is also a critical thinking skill class.

Should I drop Physical science 2 class since it’s not really necessary?
I need to have 12 units in the spring semester in order to work on campus legally since I’m an international student, so I can’t drop philosophy class lol.
If I drop the class right now, I recieve $900 refunds… I already have 9 units of elective credit, and do you guys think it’s enough at a community college?
BTW my major is political science and I have 53 units right now (After Spring semester 65 units). All requirements finished except for the critical thinking area.

Please consult the international student advisor and/or the transfer advisor. They are the best people to give you specific advice for your situation.