How to change my rescue email address and i Forgot my security questions

You cannot and need to ask Apple to reset your security questions; ways of contacting them include clicking here and picking a method for your country, phoning AppleCare and asking for the Account Security team, and filling out and submitting this form.

Because you have forgotten the Security questions/answers... it is Too Late to change the Rescue Email.

See Here > Apple ID: Contacting Apple for help with Apple ID account security

Ask to speak with the Account Security Team...

Or Email Here > Apple Support iTunes Store Contact