It's admirable to want to give back to your community. In my experience, you need to find a cause that you're passionate about. Finding something you have a passion for will make you feel more fulfilled about the work that you're doing and you'll be more likely to give back on a regular basis. That determination is going to completely up to you.
Making it to college doesn't have any impact on if you should or should not give back. Giving back doesn't just mean money either. In a lot of situations, 'giving back' is actually giving your time. This could include, going to your local animal shelter and walking dogs or socializing with cats so that they're more likely to be adopted. You could become a 'Big' with Big Brothers, Big Sisters. You could even volunteer at the local soup kitchen (or alike) and serve food to the hungry. This website shows some opportunities in your area, click here.