How well you do depends on the type, cause, and severity of the curve. The more severe the curving, the more likely it will get worse after you stop growing.
People with mild scoliosis do very well with braces. They usually do not have long-term problems. However, scoliosis can make you more likely to have back pain when you get older.
The outlook for those with neuromuscular or congenital scoliosis varies. Patients with neuromuscular scoliosis have another serious disorder (like cerebral palsy or muscular dystrophy) so their goals are much different. Often the goal of surgery is simply to allow a child to be able to sit upright in a wheelchair.
Congenital scoliosis is difficult to treat and usually requires many surgeries.