Java - charAt(), equalsIgnoreCase, if statement testing?

What I want is no matter what the user inputs, if the first letter of their input is either a 'y' or 'n' regardless of case, it will print "game start".

I've tried equalsIgnoreCase() with the "letter" variable but it gives the error: char cannot be dereferenced. Any recommendations will be really appreciated on this! Thanks!

Scanner input = new Scanner(System.in);

System.out.println("Do you want to continue?");

String wesker = input.nextLine();
char letter = wesker.charAt(0);

 if(letter == 'y' || letter == 'p'){
     System.out.println("Game start");
 } else {
     System.out.println("Game over");
 }