Hi.
It's impressive that you are able to handle a number of challenging and interesting classes and activities. Pushing yourself to juggle a bunch of different things is something that will help you throughout your life, and managing everything well is a great skill.
It's a good idea to figure out what you value and what your priorities are. While you may want to succeed at everything you do, it's more realistic to know what's most important to you. That way, you'll know what to do first or what to spend more time on, whether it's studying, tennis, volunteering or anything else going on in your life.
Once the school year gets going, figure out if everything is working for you. There's nothing wrong with dropping something if one or more of your classes is too hard, for example, or rescheduling your volunteering time if you want to spend Saturdays studying.
Knowing yourself and your habits is one way to help balance things. When are you most alert? Do you get more work done during the day (like using free periods during school to finish up schoolwork), or is it easier for you to stay up late at night? Figuring out what works for you can help you use your time effectively and get a lot done.
This is a time where being organized can help you do a lot of things at once. Depending on what works for you, you could consider using a calendar to write important things down. This could really help with your planning, since you're doing a lot of things at once, and you'll know when your busiest times are.
