Yes, you can delete your account. Just make sure that you make backup of all of your data (emails & lists) if you want to keep it.
To delete your account, click on your name in the upper right corner of your screen to see more options in the dropdown menu, then click „Profile“:
Then, click on the tab „Edit Details“ and you’ll see the option to delete your profile under the boxes that contain your profile details:
Click on the red text „Click here“ and follow the steps to delete your profile.