Along with the great information given above, I would like to share a few other things. (I apologize for the clutter of thoughts, it’s much easier if I could show you and tell you in person)
First of all, that’s good that you’re going to have a head start with those two classes. Don’t worry too much about what you did in highschool. I had 4.0+ GPAs for all my years, but had a major slump my sophomore year (2.8). Focus on what you’ll be doing at the community college now. The earlier you plan, the better. I started to plan my transfer path since my junior year of high school. That’s obviously WAY too early than necessary, but my main point is to simply plan ahead! Use assist.org to find what lower division requirements you need for the UC schools and check your private schools if they have articulation agreements with your junior college (it’ll tell you the lower division requirements and their GE reqs). It’s a little tedious for private schools when it comes to general ed, so be sure to plan out your courses carefully and see which GEs can go toward your IGETC AND a private school’s GE. What I did was I wrote down all the reqs I needed for each school and see which one overlap – go for for those first. Then, I just prioritized my top schools from there.
I’m not sure if you saw this already, but here’s the link to the IGETC course list for your college: mjc(.)edu/instruction/documents/catalog/gepatterns/igetc(.)pdf [remove the parenthesis]
What classes do you need to take? Take both your GE and lower division req, but be sure to prioritize the lower division reqs as those are the most important. It looks better when you have those completed the Fall you apply (plenty of students get rejected for missing pre reqs). You can make up the rest of your GEs the following Spring.
As for clubs and activities, join things that interest you and things that are related to the career path you want. 
A friend of mine is also Poli Sci and she is currently interning at an organization that brings political awareness to the community, an officer in the Roosevelt Institute club, and participating in a service-based club.
Lastly, definitely look into the Honors Program at your community college. They will definitely be the most helpful when it comes to transferring and is a big boost to your college app!
If you would like some more help or information, please do feel free to contact me! I help map things out for you and what not (which you can then confirm with an actual counselor). I’m a Sociology transfer student who will be attending USC and I plan to become a community college counselor in the future (that’s why I looooove working with people on transferring, haha). If you think you can handle the rest, then good luck to you and dreams can come true!