I get the error int cannot be converted to boolean? [closed]

The Java greater than or equal to operator is >=, not =>.
Where you did:
if (user => 19) …

You should have done:
if (user >= 19) …

If you ever have questions regarding this, check the Java Documentation first.

It should be written like this:
public static void main(String[] args) {
int user = 19;

if (user == 19){
System.out.println(“You are 19!”);
}
else{
System.out.println(“You are not 19!”);
}

}

You had the operator wrong in the if statement.