R.R.
Hi, my son is now 3 1/2 years old. We have been using the beginner stuff since he was little. His doctor prescribed multi-vitamin with fluoride chewable (prescription) as we are on a well also. He said not to use regular fluoride toothpaste. It is too strong for his little teeth. We now use the stage 1 for him to brush with. He is spitting and rinsing now, but not the greatest. The pediatric dentist we use does have an application that they put on after cleaning to protect his teeth that is only $10. Hope this helps!If I can help with anything else, please let me know. Good luck!