15 years old is the best time to correct teeth. It is best not to do corrective surgery such as porcelain teeth. You can also use dental arch expander to repair teeth, and then use braces to correct protruding teeth. It just takes a long time.
If you want to be beautiful, you still need to do it step by step. It will take about a year anyway. Of course, if you want to do it once and for all, then go to the hospital to make porcelain teeth or implant teeth.