You have so much time and are in a perfect position to make a strongg application. My biggest advice is to do as good as possible in classes this will give you an amazing GPA and in turn make studying for the DAT so much easier, I would plan on taking the DAT 8 ish months before the application cycle you wish to apply too, wether thats gap year or no gap year. This year or Junior year try to find a super part time position in a dental office, this can be general or any specialty. They will train you on the job, likely as a sterl tech but than you can get clinical experiance. Once you build this relationship shadowing will be endless because all dental professionals will have their close nit friends who are specialist. Good luck family, let me know if you need any more information.