You're too far behind to be honest. That fight is pretty easy that it's rare to see a learning party. Maybe T8 or T9 learning parties but not T6.

As for going into DF....I would honestly vote kick someone for doing that. It's not that someone is new to the fight but rather hasn't put the effort in. The Duty Finder is there for matching up with others, but you're highly likely to be matched up with at least a few players who know the fight and are there for the kill. Why should players have to cater to people who know little to nothing of the fight? (Honest question by the way)

It's not a personal attack on you, I just find it quite rude of players to do this.

I will reiterate, I don't care if people have cleared the content or not, but knowing what you are getting into is good. I will just as quickly take someone new who has looked up the fight compared to someone with kill "experience", as they wipe the parties just as easily.