Parents often look specifically for a ‘children's orthodontist’ for their child, which can be confusing, since there are paediatricians and paediatric dentists. It is important to know that orthodontics is not divided into separate specialties for children and adults. Orthodontists are trained to treat patients of all ages.
Although more and more adults are having orthodontic treatment nowadays, training in this field is built primarily around treating children who are still growing. Some orthodontists work mainly with adult patients, while others mostly treat children.
The most important thing is to ask for a recommendation for a good specialist, rather than looking specifically for a ‘children's orthodontist’.
This answer is for general information. Your own case needs an examination by an orthodontist.