You're doing just fine! Yes, when she eats block her poop will darken. Formula is the perfect nutrition so as long as she will take it, let her take it. If there is one feeding of formula when she is less interested, you can take that feeding out and see how she does. That might be what she needs to be hungry and want to eat blocks. Taking your/her time growing up is just fine. Just like humans, some are a little slower to grow up than others. She is doing just fine and there is no rush for veggies if she isn't quite eating blocks yet. However, when you do start her on veggies, mixed greens is always what I start with. Things like carrots and sweet potatoes are very sweet. If they start with them it is harder to get them to eat the green veggies. Just like with baby humans, you want to start with green beans not custard or the green beans will not taste as good to them.