First-my understanding of polyamory is the same as the others have said.
THAT SAID-we all get places by different routes and hell if I have a right to judge anyone on how they get to a polyamory relationship in consideration of the off again on again lying for 9 years in my marriage to get to where we are now.
SO-it sounds to me like a communication issue.
If you really want to truly communicate (versus talk) the key is as follows:
Connect FIRST then contemplate and correct each other and self as necessary.
Connect means FIRST you have to reconfirm for her that you care about HER needs and HER feelings and that you are interested in HER. Sounds a little one sided-but she's not on here-or I would say it to both of you.
Since you are the one saying you are trying
I suggest sending her a text, email or letter that says something along the lines of "hey (term of endearment here) I think I got off on the wrong foot with you. I just want you to know I love you and I'm here. If there is anything specific you want to talk about (or specifically do not want to talk about) please let me know. I love you and look forward to our next conversation!"
Then see what happens.
If she opens the conversation great. If not-work on showing her that you are interested in WHATEVER she wants to talk about.
I know for me sometimes Maca wants to drop into the "deep water" and I'm like "UH are you SERIOUS?" I need time to "warm up" and feel safe and comfortable to get into the deep stuff.
Try not to be the one to bring it up-just let conversation flow to deeper, more meaningful topics and see if she doesn't bring it up. Sometimes if a person can bring it up themselves it doesn't feel so much like they are on the spot and so they don't get so defensive.
Overall-to your questions-I would look at this as a chance to build and improve your relationship, not as a "bad sign". There are a LOT of "bad signs" on the road to enlightenment, because we all trip and fall on our face sometime.