First of all I have to give you a thumbs up
for joining this forum and seeking out help while others your age are probably at the beach enjoying their summer break. You should give yourself a lot of credit.
Its great that you are asking questions from people who can give you the best advice (those who have been through the process and know what to do and what NOT to do)
Me and probably half of all pre-dents wish they could go back to their high school years and make some changes. Luckily, you can learn from all our mistakes
I wouldnt worry about what classes to take now, because Dental Schools wont even care to see what classes you took in high school. Instead, start planning for your college curriculum.
I agree with
SayitIsntSO in that you should major in something simple. I wish I could go back and choose a major that didnt require about 40 science courses. I did well in some, and not so great in others... and in the end nobody cares if I took classes with graduate medical students with one of the most prestigous professors, blah blah blah...
I have taken over 30 advanced science courses and have not gotten accepted anywhere, whereas student X with a degree in Marketing gets accepted by having taken only the required amount. (Its really unnerving, but I can only blame myself)
Currently, and in the years to come... its going to be more and more of a numbers game. So dont put pressure on yourself to take advanced science courses thinking it will impress the dental schools - it doesnt. They will be more impressed with a 4.0 science GPA
You only really need to take about 12 science classes (including the required BCP courses - Biology, Chemistry, Physics) Get nothing less than an A- and you're straight!
Oh, and please make sure you understand everything in organic chemistry, general chemistry, and biology because it will be a blessing in disguise for when the time comes and you have to take your DAT. All the answers for the DAT exam will be given to you during those first few semesters when you take those courses. SO
PAY ATTENTION!
Thats the one side of it...
Next, I would highly recommend volunteering at a dental office. Dont wait till your sophmore or junior year... start now. (Schools will believe it when you say you have wanted to be a dentist since high school, because they will have seen the effort you put in it) And also, you will have had the exposure to the field to know whether or not this is REALLY what you want to do.
Third,
More and more schools like to see that you have participated in research. Like volunteering, you can never do too much. Find something that is remotely interesting and try it out. This is something you will probably find more about in your sophmore year.
Finally,
Make connections with all your science professors. Even if you completely understand all the topics covered, go to your professors office hours and ask them ANYTHING!!! Get comfortable with them and even mention that you have an interest in dentistry. Stay close and keep in touch... cause you will need them later for letters of recommendation and I can GUARENTEE that dental schools will be impressed if they hear from your professor that you have maintained a repoir with them throughout your college years.
I have (as usual) lots more to say but one, I am getting sleepy and two, I dont want to make this the never ending post. Sorry this was so long, but there is nothing I love more than giving people advice. (I really should stop)
I hope I helped. Feel free to PM me. Good luck!