How do I complete this codehs code

Write a program that prompts the user for their age and determines if they are a teenager. Someone is a teenager if their age is greater than or equal to 13 and less than or equal to 19.

Your program should be able to produce the following result:

What is your age? 13
Yes, you are a teenager.
What is your age? 17
Yes, you are a teenager.
What is your age? 20
No, you are not a teenager.
Hint: you must print either "yes" or "no" in your output.

function start(){
var age = readInt("Age: ");
if(age == 20){
println("Yes, you are a teenager.");
}else{
println("No, you are not a teenager.")
}