The method you chose to receive your return is not affected by the status Ready to mail, however, please view this link to understand what it means and what you need to do next:
Ready to Mail means you have to print out your return and mail it to the IRS yourself. Your taxes have not been filed yet, you will need to print them and then mail them. Unless you want to try and switch to efile.
*How to change from Mail to Efile https://ttlc.intuit.com/replies/5561257
Keep in mind Turbo Tax will always say Ready to Mail, the software has no way of knowing if or when you actually mail your taxes. And the IRS does not inform Turbo Tax when they get a mailed return.