Okay so I kind of just noticed something very recently…I’m not really in any EC outside of school. Sure I’ve been in the school’s marching band for almost 4 years now but doesn’t that still count as something in school? I’ve been a part of a few ministries at my church but I’ve never really dedicated myself to it. I’m kind of scared that colleges will look me over and think I’ve done nothing with my life. For instance I went to a UC Berkeley college tour and one of the people there said that they don’t really care too much about SAT scores of having that 4.0 but actually what you do in your meantime and how have you contributed to society. I really don’t want colleges to think im selfish and dont care for the community because I do and im always helping others in school and stuff. Anyways I’m going to be a senior next year. Is it too late for me to “really” be involved.
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No of course not. Find what you love to do and pursue it with no reservations. Don’t do something just because you think it’ll boost your college application.
Marching band is an EC. You can consider it a Music EC or a School Spirit EC - whichever.
What the UC tour guide meant is that, to get into UC Berkeley, all students must be at the top of their class - they must represent the smartest kids in their high school. So, how do you choose between two kids who’ve studied hard and gotten A’s, have chosen the most rigorous curriculum available to them, and have good test scores? You look at other factors: is that a kid I want in my classroom? is he interesting? is she going to contribute to campus life? Has he or she overcome obstacles, sown resilience, determination, drive? Most importantly for a public university, with a public service mandate: will that student represent the best there is in the state in all its diversity*, and make the most from the education s/he receives from us? Has that applicant shown qualities are few others have?
It’s up to you what those qualities are. If you have 3.75+ and are among the best SAT scores in your high school, you’ll likely make the first cut (= “can do the work”). Then, they’ll look at your essays (very important) and what your qualities are, as demonstrated by what you’ve done. (“I am generous” is of no value, “I have spent many weekends and evenings (… hours according to records) raising money for the … charity, and through my initiative organizing a used clothes sales involving not just HS students but also adults from the community and various out reach programs, we reached $…,000 which were then given to a fund dedicated to…” <- see the difference? One is bragging, the other is showing who you are.)
Since you’ve been involved in ministries at your church: time to step it up. It should be easy 
since you’re already involved and churches rarely refuse volunteer help.
Marching band is a good EC - is the marching band good? Have you gone to States? Since you play an instruments, do you take lessons outside of school? Do you play more than one instrument? Do you play in any other sort of musical ensemble (informal jazz or rock band, church ministry…)?
Can you join another club in another area - could be Latin Club, FIRST Robotics, cooking, welcome international students club, SADD…- and get involved?
All in all, it’s not how many activities you do, but how in-depth that involvement is. For you, clearly, your two areas of “deep” involvement would be music (band) and church (ministry). With a light third one that you could try to get more in-depth about, you should be fine.
- here, to be understood as: socio-economic, geographical, rural/coastal/urban... race or ethnic background is NOT taken into account.