When you created your account, you had to input a mobile phone number, confirm another recovery email, and confirm a two-factor authentication. This two-factor authentication will allow you to have up to 10 one-time codes that you can use after you gain access to your account.
If you do not do this and you have a free account, the alternative is creating a new account.
People forget the jumble words over time, and Google makes it easy to regain access.
How do I recover my Gmail account if all else fails?