OP, relax
you have a lot of time to go before you apply to college.
btw, colleges dont care what you did in middle school.
so just take the classes that interest you in HS, and check in with us 3 years from now.
:)>-
Don’t worry about 8th grade in terms of college - colleges want to know about you after starting 9th grade. When it is time to pick classes for 9th grade your school will help you - many 9th grade classes are required such as taking a math and English so see what your school wants you to take and don’t worry about what others elsewhere are taking since high schools are all different and colleges know that.
Chances are your middle school has a guidance counselor who will help you pick your classes for 9th grade that are the right level for you and will help you know what options there are for electives. I’m not sure what your looking to add to 8th grade academics. Some fun things my kids have done is spent time learning some words in a language not taught in school (in their case Hungarian) using programs like duolingo. We have a local public access television station which has low cost youth classes they have taken over the years and learned basic film production and editing skills. Many public libraries offer fun youth programs as well. You can try to find a fun sounding free program on couresa or edx to do online. See if anything on scholastic art and writing interests you https://www.artandwriting.org.
What classes are you taking right now and are any more rigorous courses available at your middle school?