How to reset my security questions?

See if you can reset them : If you forgot the answers to your Apple ID security questions

If you can’t reset them yourself contact Support in the country where you live (and which is therefore the country on your account) and see if they can reset them for you : http://www.apple.com/support/itunes/ww (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)