Can you let me know what you have done so far to get into it? Did you click on forgot password? Do you have a 2nd email account connected to your gmail? Did you connect a phone to your gmail just in case you forgot password?
Did you connect a phone or a 2nd email account to your old email?
Did you go to this link to recover your old email address:https://accounts.google.com/signin/recovery
What is your old email address?