I took college classes when I was still in high school. My senior year I only had two classes at the high school and 2-3 at the college, sounds like you're doing something like this. The other students will see you as a child (because you are) so try to be mature and respectful. Respect your professors and go to them early if you need help. College has a liberal slant so keep that in mind when expressing yourself - doesn't mean you can't challenge the narrative, but don't detail class discussions.

For example last semester I took a climate change class where we did a mock COP negotiation (like they had in Paris last December) and at the end I brought up how none of us really understood the competing geopolitics between rival states, and how in the real world nobody holds hands and sings Kumbaya "let's save the world" but in reality there are military rivalries and economic rivalries and criss crossing alliances between things like NATO, the SCO, and BRICS. Literally right after I said this the professor played a clip from the COP in 2012 where negotiations broke down and the BRICS countries made a secret deal.