The role of mentor is open to anyone who feels they have something of value to offer the people they will partner with. There are no set qualifications for becoming a mentor beyond an enthusiasm for helping others and celebrating their success with them.
Ideally, as a mentor you should feel fairly confident in your craft and have been writing for at least a few years.
If you are published, have qualifications in creative writing, or a background in publishing, feel free to add these details to your mentor profile. By sharing what it is you offer, you help your potential partners feel more confident that you are the right mentor for them.
There is nothing stopping you from being a mentor and recieving mentor support at the same time. We are all of us still learning.
For more information check the Mentors for Writers entry on our blog.