Orthodontic treatment, whatever the appliance, can be started at any age. The important conditions, of course, are the patient's own wish to have it and the health of the teeth, gums and bone. Above a certain age, the likelihood of gum problems increases. It's important to pick these up in time so that steps can be taken to treat them. If the teeth and the surrounding tissues in the mouth are healthy, there is no contraindication to orthodontic treatment.
This answer is for general information. Your own case needs an examination by an orthodontist.