The position of gum shift can either be recession or gum overgrowth. In cases of recession grafting is one of the treatment modalities. Considering your age, knowing the causative factor is more important than just treating it. If the causative factor persists even after treatment, there are chances of recurrence. Treatment cost would vary depending on the type of surgical procedure.
Next Steps
Visit youe dentist or a periodontist (gum specialist) for a better idea