Find a designer you get along with. Ask yourself ‘If it all goes bad (which it possibly will a couple of times during your branding project) do I think this person is the kind of person I can go through a minor conflict with and stay in my integrity?’. Because if you already feel a bit funny about your designer, I can guarantee you - it’s probably going to get ugly. 
I liken building a doing your branding with someone, to having a baby together. Without being overly dramatic - it really is! It’s a creative project. It’s YOUR business presence. It’s going to make you a lot of money if you do it right. And it might cost you a few dollars. 
So take the time to find the right designer. Test out their sense of humour and use your intuition. Your gut knows.