I never did buy the stage 3 jars. My kids ate stage 2 until they started eating our table food. I didn't feed them the whole jars either. I had a divided dish and would put 2 Tablespoons of a noodle type food, veggie,(sometimes 2 different veggies if we didn't have a noodle type) and fruit/sometimes mixed the fruit with rice cereal, then had a 4 ounce bottle after they ate. This is what they usually ate for lunch and dinner so their baby food jars lasted a few days. I didn't feed them out of the jars so they wouldn't get bacteria mixed in them from their saliva off of the spoon. Use the divided plates, they work out great and 1-2 tablespoons is a serving for most foods at their age even table food.
Just keep introducing new foods and you will figure out what she likes. Sometimes they will eat that food they didn't like before a week later so keep introducing foods at different times, even if it's just a bite, she may like it the next time around. Toddlers are hard to figure out. There were times my kids loved a certain food and knew they really liked it but they wouldn't eat it sometimes and acted like they didn't like it, but the next time we had it they would eat it again and love it.
I guess the saying they eat what they need shows truth at times. It is frustrating though and we have all been there.