Is it normal that my baby's teeth have not grown in?

Yes. Most babies get their first tooth between 6 and 12 months of age. If your baby is less than 12 months old, he/she is perfectly normal if you are still waiting for the first tooth. Some babies will get their first tooth earlier than 6 months and occasionally a baby will be born with a tooth.
Yes. The average first tooth appears at about 6 months. But some babies don't get that first one until as late as 15 months. If your baby is normal, healthy and is growing and developing well, then he will eventually get teeth. After 15 months with no teeth, you may want to consult a pedodontist, but absence of teeth is an exceedingly rare phenomenon.
Not abnormal. some children will get their teeth earlier while others later. When children's teeth come in later than average, it is called delayed tooth eruption. If concerned see a pedodontist, dentist for kids. Good luck.
How old ? How old is your child? There is a wide range of eruption times that fall into "normal".
Age? Although some children are born with some baby teeth in place (rare), most have teeth begin to erupt at 6-12 months, but may be as late as 18 months (unusual). As pediatric dentists are trained in oral growth and development, take your child to a pedodontist for their first check-up at age 1, even if teeth are not present. Get an evaluation from a pro. And by the way, 1st orthodontic eval @ 7.
Yes. Babies usually get their first teeth (lower middle 2) at 4-10 months, and the upper middle two incisors at 8-12 months. That means a healthy, thriving baby may not have any teeth until after age 10 months. Babies seem to start drooling around age 4 months, regardless of whether they have teeth coming out or not.