Wait at least a few years, that way you'll know whether it is the right decision for you. Obviously, it will be scary if you do get it done, but you should be certain that it is the right decision. If you're not sure about doing it, then wait until you are sure. In the meantime, there are probably some exercises that you can do to help your back.
You can probably find some online, but if you're not sure, try pilates or yoga, or ask your doctor or osteopath. Good luck :)