You 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.
They wouldn't be security questions if they could be bypassed without Apple verifying your identity.
Alternatives for Help Resetting Security Questions and Rescue Mail
4. Fill out and submit this form. Select the topic, Account Security.
5. Call Apple Customer Service: Contacting Apple for support in your
country and ask to speak to Account Security.
How to Manage your Apple ID: Manage My Apple ID