Yes, it is normal, she is still young and unsure about them. Dogs indentify adrenaline flow (and what probably these dogs give off) by smell, but adrenaline means both, and fear, and agression. When two dogs meet nose to nose, I believe, it's still running, but then they choose what to do next. But, if it happens, especially if you say she's growling, it is her who starts adrenaline rush first. There is one trouble, she might get used to it. Don't wait, as you don't have much time left, she will be an adult in six months and you will start dealing with agression. You need classes for her to change her opinion about other dogs.