Don't forget to take backup or download your all email data before you want to delete your email. If you want to delete your previous email account and want to create a new email account take necessary backup of your all data. In download centre you will be able to download all your +1s data, Buzz data, Contacts, Google Drive data, Google+ Circles, Google+ Stream, Picasa Web Albums, Profile, Reader, Voice data. You can download your data in two ways. Follow the steps to download your email data...
1. Signin to your email
2. Click gear icon and then click Settings
3. Click Other Google Account Settings
4. Click Download your data
5. Again click Download your data
6. Click Create Archive
Once you click create archive Google will starts archiving your all data in a single file. If you select check box Email me when ready Google will send an email when archive is ready for download. Click the link ready in the mail that Google send you or stay on that page and when archive is completed then click Download.
Click on the link to sign in to download centre and click Create Archive. Once your archive file is ready you will able to download your data.