It's like swimming, unless you jump in, you never know if you can. Besides, there are no right or wrong answers, it's your first reaction to a submission without premeditation. You must come next time.
@June Whitaker yes, please join us next time! You don't have to make any comment at all, if you don't want to. You can just observe silently! It's very useful to see what justifications are made for taking a submission further or for rejecting it outright. It would definitely give you food for thought in relation to the future presentation of your own work.
It's a great learning process. Makes you think about your own work as well as the subs you read plus a great insight into what'll happen to your submission when it arrives at a publisher's. I definitely recommend it even if you don't want to comment on anything.