Usually not. Delayed teething (eruption) is considered when no tooth erupts by 13 months age. Cause is usually unknown or familial, occasionally is associated with hypothyroidism or hypoparathyroidism.
Teeth are variable. Some babies have a tooth erupted at birth and some erupt their first at 15 mo. The variability is well established & later eruption is no reason for concern. The average is 1/mo starting @ 4-6 mo & those who erupt later often do several at one time.
Maybe. The first primary (baby) tooth to erupt is the lower front tooth and it usually comes in around 6 months of age. If your child has no teeth visible, I would recommend a visit to a pedodontist. It is possible that some teeth have not formed in the bone or it could be that the gums are fibrous and the teeth are there but cannot break through the gum. Or you could simply have a late bloomer!