You can easily reset your password by visiting https://www.theaa.ie/my-account/forgot-password
Enter your email address and click "Send Reset Link". You will then receive an email with a unique link. Simply click on this link and it will open a window in MyAA prompting you to create and confirm your new MyAA password.
Note: For security reasons the password reset link will be valid for 24 hours. If the password is not reset within this 24 hours window, you will have to request another password reset link.