Honestly, it is really important for the deaf child to have assessment by evaluators who are experienced in working with the deaf child, and preferably fluent in ASL. Studies show that evaluations are way more accurate with experienced evaluators. If your district can't offer that, then perhaps you could request an evaluator from your state school for the deaf. I know that some state schools have evaluators who do outreach and work with mainstream programs in the state.
I know it's really tough for someone who is not fluent in ASL to be able to tell what is developmentally on track or not, in terms of signing skills. That is when it helps to have an outside person come in who has more experience and fluency in ASL.
I'm a Deaf mama, and have two children- one Deaf and one hearing. They are both developmentally on track in language- in ASL and spoken English for my hearing child and ASL for my Deaf girl. It's really difficult to accurately evaluate a deaf child for language skills, though, due to all the conflicting factors- fluency in language models, diverging methods of teaching, the role of speech training, etc etc. My 2 1/2 yo uses classifiers.... not role shifting yet. My 5yo does. I think what you could look at is the complexity in communication, the understanding of irony and humor. You don't need an understanding of classifiers to do that, yes?
But ultimately, because your child is deaf, she should continue to receive services whether or not she tests developmentally on track.