i take her to a gsd training class every week shes fine there

Guest it wis normal for dog to want to interact with each other, so are you letting her play with any dogs?

If you took your children to the park you would expect the4m to want to run over and play with the other kids right? 

For good manners of course you woudl probably as the parents if it was Ok for your child to play with theirs, so the same applies with your puppy, as at a year old that is what she very much is.

If you never let her play with other dogs you meet she will be very frustrated and all the more keen to pull over to see them.