When I first began my journey, I really did not understand the significance of a Matron Goddess or Patron God. I was confused about how to figure out who s/he was, how I would know I had found the "right one," etc. For years, I just sort of "tried out" different deities to see if I found any alignments. I started with the Celtic Pantheon because I have Celtic ancestors and worked very briefly with Cerridwen. After the Celtic Pantheon, when I felt that my time with Cerridwen was over, I moved on to the Egyptian Pantheon, since I'd always felt a strong connection to it. I tried my damnedest to avoid the Greek and Roman Pantheons, since they seemed so common. But, early this year or maybe even sometime last year, I kept dreaming about Hekate and seeing her in my dreams, and it seemed that every time I searched for something online or in a book, there she was.
After a lot of meditation and soul searching and asking for guidance, I finally figured out that Hekate really was sort of calling to me. She's been with me ever since.
I don't think that you HAVE to have a Matron/Patron deity, but sometimes it's nice to know exactly who you'll be working with and who is with you. I realized how strong my connection to Hekate was when I started realizing that every time I read about her, I got this warm, tingling feeling in my soul and body. It's like the love of a mother being showered on her only child. I can not even begin to tell how wonderful it feels to be connected like that.
So you think you might have found YOUR Matron/Patron deity, but how do you know? Well, like many other things in life, you will just KNOW. There's no way to tell you what to expect, but you will feel a connection and they will just click with you and your soul. That's all I can think of to describe it. But you really will just know when you find them, or they find you.
Just because you have a Matron/Patron deity does not mean that you can not work with other deities as well. There may be some things that you feel another God(dess) could help you with more (or differently) than you Matron/Patron. That's ok. You won't be struck down for working with other deities.
Throughout many of our lives, our Matron/Patron deities may change many times. That's ok, and even expected. The Matron/Patron deity you work with is probably in your life to help you through particular phases, transition periods, etc. and then you may find a new one. Embrace those changes and know that each new deity probably marks a new beginning in your life, or at least the beginning of a lesson that they will guide you through.