It is normal for poo to change with the introduction of solids, and will also change depending on what you feed her, how much and how she responds to those foods. I think you're right to be cautious though as you don't want her to be constipated.
As she is still young for solids I would probably reduce/stop her solids for a few days to give her system chance to settle down again.
I think a bit of trial and error mixed with mummy instinct will help guide you as to whether her poo is normal or becoming too firm and a food diary (including poo frequency and whether it was hard etc) might help.
Babies do look like they are struggling and use their whole body to push a poo out, that's quite normal and the poo can be a normal (firmer but normal) consistency. You don't want her poo to be small and hard though.
You could try a little prune juice (a small amount) and see how it effects her poo. It would likely be better for her if she can push the poo out without your assistance but you don't want to cause her to have diarrhoea either - solids poo is going to be firmer and is going to take time to learn to push out.
I used to give a prune rather than juice, half a prune or one prune as finger food if mine was getting a bit too firm, and I gave carrots if he was getting a bit loose - this way I could monitor each day what was needed to keep things moving and comfortable for him in a natural way. (he was older than your LO though and was ready for finger foods)
This might also help
Constipation and Laxative Foods