Strange invite

There is a dancer that I've known over a year now. We are friendly and I spend on her, but not a ton. A couple of dances here and there, a drink once in a while.
A few weeks ago she mentioned her birthday was coming up and then yesterday she invited me to join her and her friends to celebrate at a restaurantand gave me directions. There was no otc vibe and I have never asked.
Anyone had a similar experience?
Seems weird that a friendly acquaintance gets an invite like this.