Hi S.,
I am a dentist and this is what we are taught in school regarding a first visit. It should be within 6 months of getting the first tooth. This allows the dentist an opportunity to make certain there are no problems to catch/prevent and also a great chance for parents to see what techniques work well and what is appropriate for your child.
I read in another post that it was recommended to wait until age 3...ABSOLUTELY NOT! This may be the dentist's preference but not in the best interest of the child patient. A pediatric dentist or a general dentist that can handle young kids knows that age three is often way too late and big problems CAN already be in place. This leads to unpleasant and costly visits for both the child and the parents.
Early visits are so important. They establish a trust between the patient/parents/and dentist that will last a lifetime.
Hope this helps and keep up the good work with brushing!
Dr G.