One tooth

Brittany

So I'm a little worried. My 11 month old has had one tooth for about 3 months now. I'm not concerned that she doesnt have like 6 teeth, more like why hasn't the one next to it come in yet. Normally teeth come in pairs. That's fine, it's normal to only have one come in sometimes. But 3 months? I dont see any sign of the other one popping up yet. Is it normal to only have 1 tooth for an extended period of time?