If you create a new site in your Yola account, it will not delete the existing sites that you have. If you are using a Yola Free account, you can have up to 2 sites in your Yola account. With Yola Bronze, you can have up to 5 sites. If you upgrade to Yola Silver or Yola Gold, you will be able to have up to 25 sites in your account.
For more information, click on this link: Yola Packages.