You can definitely handle all of those activities, but I’m not sure if you would be able to do a lot of the “world-changing” you want when you have so much going on. You can choose to do a lot with a few things or a little with a lot of things. That is up to you!
And Re: the graduate school question, it’s a little early for you! I would start asking those questions when you get all your undergraduate offers/financial aid back from colleges. Balance the pros and cons. Yes, usually if you are dead set on gradate school, you should be saving some money and maybe opting to go to a cheaper school. But oftentimes plans change. I would wait until you’re there to start planning that ahead!