From a purely physical point of view, you should wait until your body has finished the body changes associated with puberty and adolescence. The next thing to consider is the patient's overall maturity level, which can only be determined by having a good dialogue with the patient.I'll give you an example, my own daughter wanted breast implants at age 17. We made her wait. As it happens, once she got on the pill (on her own, at age 18), her breasts changed and she is happy now with her size.I don't know how old you are, but if you are below age 18, you will be better off by discussing this with as many of those adults close to you as possible.
Generally you should be at least 18 years of age. If you are an emancipated minor, you could also qualify but the surgeon may be somewhat reluctant to perform this.