I have to agree with Sally's Mom but also that 5 months is a terrible age to evaluate a puppy. Colleen Williams (Southern Goldens) used to tell me that she figuratively locked her puppies in a closet at 5 months and tried not to look at them conformationally until at least a year of age
That said, it is easier to finish a dog in Canada than in the States, so it is hard for me to say what would finish and what wouldn't.
What does your breeder say? Was she a show pick? Your best shot for a mentor is your breeder. They know their lines, how they mature and should be experienced in showing dogs.
And, if she has a strong English background, they can be VERY slow to mature. I have a girl from an Australian import and to be honest, I have been very disappointed in her conformationally for quite a while. She seemed to be rangy and lanky, to lack bone and I wasn't thrilled with her angles and even her head seemed to have changed. I had been told this can happen with her lines. Luckily, she is super smart and very focused
In just the last month or so, things have suddenly changed-her head is back to being very nice, her neck has reappeared, as has her coat and I swear she has added bone! She is a very pretty girl now.
So, check with your breeder to see if her lines are very slow maturing. I assume that at least one of her parents is finished-check and see at what age. That can help you determine if that dog may also have been slow maturing. I have always had very slow maturing dogs, but Suva was slow maturing in a whole different way.