Impacted canine

I don't know if anyone knows about this but I'm at a loss. Our 11 year old son lost his left canine several months go and we only see a small bit poking through. He was seen by orthodontist in December and she didn't mention any problems. She said there will be enough space for it. He also had a panoramic done about a year ago and she didn't say anything then either. Isn't that how impacted teeth are identified? Can it take this long? I don't think the one on the other side took this long. Thank you.