Responding and answering an email are two different things. By replying to all requests to set the expectations of the sender, you'll end up feeling less overwhelmed.
Done incorrectly, hiring someone can cost you more time than it saves. Embrace your new role as teacher, and you and your growing team will be firing on all cylinders.
No matter how much email you receive, there is always someone who gets more. So how do they keep up? By not answering every piece of communication that comes across their desk.