As you can see, there are a variety of answers. I'm sure that's confusing.
So let's start with WHY you gave her 1st foods, let alone 2nd foods. Did the pediatrician recommend it? Has she not been gaining weight? Did the doctor just feel that "it's time"? Some kids don't start until later, some kids never eat baby food, just your food pureed and ground up, and some kids start earlier than 5 months (mine did, on the pediatrician's recommendation).
Adding foods changes the consistency of her poop - so are you just noticing that it's not runny like breast milk stools? That's completely normal, as others have said. You'll see more and more of that as she gets older and as her diet increases. However, there's another issue - do you feel she is constipated and having trouble with her bowels? If the latter, put her in a warm bath and also move her legs while you are playing with her or changing her. Bend her knees and put her legs up closer to her abdomen, as if she was in a crouch position. Move them up and down, gently. That can get things moving.
As others have said, 1st foods are single foods (fruit, veggies usually), and 2nd foods are often combinations and less watery. The idea is to get the child used to swallowing and working with thicker foods in preparation for full table foods. In the beginning, they can only manage the real liquidy foods.
What else are you giving her? How much breast milk or formula? If she fills up more on solid foods, she's taking in less formula and breast milk. That can be a problem for 2 reasons: 1) breast milk and formula have more nutrients, while the baby food only has a few. 2) And this is important - milk/formula have LIQUID and she needs that water to keep her poop softer as well as to hydrate the rest of her body. So you may find she's much reduced in water intake. In the short run (very short run), I'd give her some water in a bottle to just hydrate her. Do an ounce or so several times a day.
Please call your pediatrician to discuss all that you are doing and what the result it. Your child's doctor has a 24 hour line - usually it's the regular office number, and after hours and on weekends, it will go to an answering service. If your child does not appear to be in distress, this can wait until Monday. But call then and discuss it with a nurse, and possibly get a call back from the doctor. And don't wait a week the next time and then go on the internet - call your own doctor, who knows your child and who will get back to you much sooner. We are just moms, not doctors, and we don't all agree with each other - each kid can be different, and your doctor or nurse can ask you the questions we are asking you, and many more.