How get value from other component in react js? : I try get value from other elements with help props, but not worked. My logic, when load the main.js makes request to the child.js and I get the age, but not works.

    class Main Connect extends Component {
       constructor(props) {
           this.age = this.props.age
       }
 
       render() {
          <Child />
          return(this.age)
       }

    }

    class Chaild Connect extends Component {
 
       render()
          return(<Main age='21' />)

    }