Correct. As long as they're getting enough calcium from either their feed or supplemented oyster shell, etc.... I wouldn't worry at all. I kept pullets from three hatches this spring (Feb, March, April) and still regularly get soft-shell or shell-less eggs, among all the pullet eggs.
AH so that's the answer. She's still a pullet. Soft shell eggs are common in pullets, as their bodies are still figuring out how to manage the whole process. First come the pullet (small) eggs, then a variety of fairy eggs, soft shell, or shell-less eggs, or huge double-yolkers. Sometime before...