Share 'Teeth'

My son is 13 months old and still only has his 2 top and 2 bottom teeth, he got those between 6-8 months...should I talk to my doctor or is that normal? I just want him to be able to chew food better so I don't have to worry anymore...I also feel like he's been teething forever. He drools like crazy and bites everything in sight!!! Anyone else's kid go for that long without getting teeth?