There are lots of reasons feeding and sleeping patterns change, and hunger is only one possibility. If she's been ill, that's far more likely. Also, it is a common age when these things just tend to change anyway.
A healthy, full-term baby gets everything they need from breast milk for *at least* the first six months. Sometime after that they begin to run down their iron stores and need a complementary source of iron and zinc, that's all.
Developmentally speaking, if she's sitting up unaided, has lost the tongue-thrust reflex and is able to chew and swallow, then she's ready to eat.