Google has been changing its layout lately, making it difficult to find things. There is a possibility that the layout will change again, but if you want to delete your G-mail account as of the time of this writing, follow the steps given below.
Step 1: Log into your Google account.
Step 2: Click “Products” on the left side of the Account Settings page.
Step 3: Click the word “Edit”, found to the right of “Your products”.
Step 4: Click “Remove Gmail permanently.