I've heard that they should go as soon as they have teeth. So, your little sounds like he fits the age for it. You might want to make sure to get a pediatric dentist too. They are really geared to little ones.
With our first, we'd been told not to go until they are 2 years old. So we didn't even put her on our dental insurance plan until she was two. When she was 18 months old, she fell and chipped her front teeth. People told us she would be just fine, plus, we didn't have money to take her to a dentist. To make a long story short, as soon as we could, we added her to the dental plan (when she was 2 yrs old). They checked her broken front teeth and both had cavities because they weren't treated right away.
Whether you actually go to the dentist or not, by the time they have teeth, make sure you add them to the dental plan so that if by chance that happens to you, you'll be able to treat them:-) We felt pretty bad that we hadn't added her when she turned a year old.
Our son is 14 months old and we have added him, but we have never taken him in. We probably won't until he is two or unless something happens to his teeth.