My five month old has a visible tooth. is this a little earlier than average?

A little: Six months is the average. However, this varies greatly and is well within the normal range. Here a chart for your future information but don't get too concerned as to when the teeth start to erupt. It all works out in the end. Have your child seen by a pedodontist by at least the age of one year old. http://www.ada.org/sections/scienceandresearch/pdfs/patient_56.pdf.

Slightly: Many children begin erupting teeth at six months.

Around 6 mo: So yes it's a bit early, but still within normal range.

Almost perfect : Timing for your precious child to begin showing deciduous teeth. Usually the lower front two "baby " teeth come first, followed closely by either two more lower front teeth immediately adjacent to the first two and/or the upper front two middle teeth. You can some times witness 6-8 teeth erupt rather quickly. Enjoy! he/she will be in college very very soon !

A bit early but..: While it is a bit early, it is not unusual. Tooth development charts are based upon averages not exact time frames. It just means that as a parent you need to start that much sooner keeping these teeth clean. Contact your local dentist for ways to help keep your little one's teeth healthy.