Ideally, this volunteering will help you get into a college/university. You will have to continue volunteering during undergrad. Places at soup kitchens, food pantries, working with those who are less fortunate.
Right now your plan should be to mitigate as much debt as you can. Going to a state school will help. Going to a school that has a dental school can also help. But it really doesn’t all begin until once you start college. So try to learn how to study effectively, do well on the SAT or ACT to get scholarships (and help you prepare for the DAT) and just have fun. High school is less stressful than college so also learning how to cope with stress will also help. Do anything you can do to help you prepare for college since what you do in high school doesn’t matter as much for dental school.
For ACT, I’d try to aim for a 30(generally cut offs for scholarship), SAT I believe anything higher than 1400 is a solid score. for the DAT you should aim for a 22AA+. The ACT will be easier, for the DAT you should try to take it after you’ve taken ochem so it’s fresh in your mind. Usually that would be sometime after your sophomore year (if trying to go immediately after graduation, otherwise during junior year or fall/spring of senior year) I took mine after the first semester of junior year which ended up working out well for my app.