In order to become a professional wrestler for the WWE or almost any other wrestling faction you need to first got to pro wrestling school. The minimum age to go to pro wrestling school is normally 18 years of age but some schools may allow you to start at the age of 17.
The average starting age of professional wrestlers is eighteen, due to legal reasons and liability. WWE requires students to be eighteen or older to participate in its Florida-based wrestling school.
You can start by getting in shape and staying healthy. You will need wrestling training and experience. Contact a local wrestling club or find a company that travels around the country offering training seminars you can attend.
You should become versed at amateur wrestling, get and stay in good physical shape and good cardiovascular shape, and practice delivering a promo, not just yelling, but conveying a message.