I don't understand why you invited her in the first place if you aren't close to her at all (it sounds like she is more friends of your friends than your friend).
She may have thought you were trying to pull in extra presents by inviting her.
Obviously, I doubt that is what you intended.
But people do this. All of a sudden they are getting married, you get an invite in the mail, and it's like "****, I barely know this person, and they are expecting a present?!"
However, she could have declined.
Anyways, don't fret about it. Just focus on enjoying your good friends and your new marriage.