I can completely understand your concern about deleting the WhatsApp group that you have started. Unfortunately, it is impossible to remove a WhatsApp group even if you are an admin.
One can not delete a whatsapp group permanently. Irrespective of you are a member or admin. The only option is to exit from the group and deleting is not an option. You can not delete the group completely from this universe. Please tap on the group and scroll down to the "Exit Group" section. Click on and confirm your selection. You will no longer be a member of the group.
If you are leaving a group in which you are the only admin, another person will be assigned as admin automatically. Please note once you are deleted from the group, you will not be able to join the group again without the approval of the group admin.
I also found a youtube video that may help you. Please watch the video at: