Hi Sabrina,
You'll find that everyone has their own view point on certifications. I think that it really depends on the individual when it comes to the value of it. The focus should be on the skill learned and not so much on whether or not you're certified. My suggestion is to focus on courses that will add value to your business. And by value I mean courses that will teach you something you don't already know or ones that will help you sharpen skills you already possess. In order to be a successful business owner, you should always be learning.
I am not sure if REVA Network is still operating but I know that Pam Ivey has a Real Estate Assistant course that can be found here:
http://pamivey.com/reacert.html. I haven't taken it but I have heard great things about her.
All the best with your business,