the normal timing, when the baby first start having teeth eruption is 6 to 7 months. But in a few cases it may be delayed by another 6 or 7 months for some local reasons. As your baby is now almost 15 month old, teeth must be on their way in oral cavity by maximum of next one or two months. you can feel them by rubbing against the gums of the teeth, which appers swollen and with slighted elevation of crown portion, that can be felt.
Also, Kindly pay attention on skin/ nails and hair of the baby. if they are normal, there is little to be worried about.
if still it doen't happen, ask for a dentist
opinion, who can perform a xray of jaws and can make sure presence of the teeth.