I don't know what my sons level was last year before starting supplements, but now after supplementing with 1200 IU per day for about a year, his D level is 22. We live in Seattle, so low vit D is not uncommon, but I was surprised that it was still so low.
When I got his lab report it said that 30 was the minimum "normal" value, so your kiddos level is low end of normal by that.