What would be the first stage I could do to become a singer?

Wow great question Carlie!
Great singers can always put on great shows. You may want to first look into taking some sort of voice lessons or just learning to control and contrast your instrument ( your voice) this is important to nuture your voice so you can sing and hit notes to the best of your abilities. Do you know what kind of music you are interested in just yet? For individuals your age you may want to look into a school choir to learn the basics, or even a play or small performing arts shows in your area. There are many performing art programs that look for people every year to join the cast and crew. You may want to search these people out with the help of your parents and take lessons if so you are able to. If you are unable to take lessons then plan b. The internet YOU TUBE has free voice lessons just type in how to sing, or voice or whatever you are seeking to learn. I am sure you will do just fine. Now once you start with that I think you are on the great yellow brick road of singing!

I will happily address your question about “the FIRST STAGE (steps).” For me and most singers that I know, the first stage begins the first time you hear a voice. It can be your mother’s voice, or even your own voice. To you that will be music. We all instinctively begin cooing and making sounds, gurgles, and noises before we learn to form our voices to make words. This ‘first stage’ is where natural ability begins. This is where the inclination to sing cannot be suppressed. The first stage does not originate as a singing lesson, or in joining a choir, although those things can be added later as you desire to grow musically. Your first stage includes but is not limited to, singing in the shower, singing along with the music on the radio (TV, Computer, Pod, or cell phone), singing to the rhythm of your own footsteps on the side walk, or with your friends while riding in the back seat of Mom’s SUV. The more you sing, the more opportunities will come to you. The song and the music will find you. Following your first steps there will be ‘Open Mic’ opportunities at local office shops, church, school, and community choirs, classes, workshops, and networking opportunities for voice & instrument. Hear yourself before you move to the next stage, by recording yourself and listening back. But the first stage is the most important which means to just start SINGING. (to begin the next steps find others who have interests in singing and join the fun, check local meet ups https://www.meetup.com )