I guarantee she will love it.
6 weeks down the line from now she'll know all about the rituals and routines that they do in the classroom. You think it looks chaos and not organised, but it isn't at all.
Our dd took us around her class after 5 weeks. She showed us where you hang your coats, where you use the toilet, the snack table (you take your name card and put it in the bowl so the teacher knows you've had your snack) you pour your own water (I know, I freaked at that too but hey I watched 9 x 3 year olds all do it without spilling a drop
) where you wash you hands (I have to roll my sleeves up mummy); she pointed out her pictures on the wall, her favourite teacher and 2nd favourite one (the TA) and the chair she sits on at story time....this list goes on and on.
It's free play but with certain practices every day. Dd's class is large, 26 but there is a green group and a blue group so 13 in each. They do the days of the week each morning after register, then free play and snack table open, with certain activities guided; then tidy away and story time; coats on and home time. They encouraged to go outside come rain, wind or snow.
You're worrying far too much and it is likely because you've not asked the right questions whilst there. Did the teacher talk to you about EYFS? What they'd be doing this term? Is there a newsletter or website? It was all brand new to me, being a parent of a child at 'school' (albeit nursery) but you have to search for the information - the school will assume you have. Check the schools website, there should be a ton of info on there.
And finally, relax. She'll love it and it will go so quick you'll wish she was there longer 