I agree with Nicola.
Don't worry about puppy class. Your worries will transfer to her and then she really will be fearful. You have to treat everything like the grand adventure it is, so you have to adopt a very happy go lucky attitude.
There is nothing wrong with going to puppy class and just sitting on the sidelines and soaking up things, don't put any expectations on her or yourself. Just go, take some yummy treats and toys and play with her there, and don't require her to
do anything. Just let her take it all in, and like Nic said, talk to her in a jolly upbeat way, and lots of praise and reward for anything "brave" that she does
Same with going out. It's supposed to be her time, so if that means that you sit in the drive and just take in the big world, and play and treat or praise for bravery, then so be it
Just relax, there is nothing to worry about (bridges should be crossed when you come to them, not worried about). Take the pressure off yourself to be a "perfect cocker mum" and the pressure off her to be a "perfect puppy" and things will fall into place. Patience, calm and happiness, those will be the keys