The cut is not good-looking, and the single eyelid is very cute. Don't destroy the beauty of nature. What if the single eyelid is popular in the future? There are too many cases of cutting failure around me, and I regret it. Are you willing to gamble on your future life? Even though the technology is much better than 10 years ago, the cost of failure is heavy. Besides, your sister is only in the third year of high school, and the days after that are still very long. Plastic surgery needs careful consideration. If you really like double eyelids, you can use double eyelid glue, which is very common in the market and has similar effect, but it will give you a chance to regret it. If you don't like it in the future, you can save it.