I'm not sure if we can tell you the ins and outs of dentistry since most of us are not yet in the profession 😉
However, it's a great career field to get into! You get to help people out, work in a stable job, and you can live comfortably.
Yes, you need to get a bachelor's degree before you get into dental school. However, there are joint bachelors-DMD/DDS degree programs that you apply for during high school at the same time as your college applications (it sounds like you're still in high school?). These are competitive programs where you do like 3 or so years of undergrad, I believe, and then you go to the partnering dental school (you still have to take the DAT and maintain a good GPA). You might not get into them, but then you can just go the typical route of getting a bachelors degree and then apply to dental school. Dental school on its own is 4 years just to become a general dentist. If you want to specialize, then that's a couple more years of school on top of that.
Hope that helps a little! Good luck 🙂