There's really no average age as to when a child's first tooth falls out but usually some children begin losing their first teeth around age 5 or 6 and then by age 8 most children have lost all their baby teeth and then new teeth should have grown in.
I started losing my first tooth around age 5 and then by age 8 all my permanent teeth grew in place.
Some children may start losing their baby teeth as early as age 4 but most don't start losing their baby teeth until around ages 5 and 6 years of age.
Kids will certainly start losing their baby teeth at 6 years of age though but it can vary from child to child as everyone is different.
There's no need to take the kid to a dentist to pull the baby teeth out as they will naturally fall out on their own and I've actually pulled a few of my own baby teeth when they became lose enough.