Hi. Well, first. There is great positive in a well liked, socially content kid. I have an academically successful child that lacks the social situation your child has. I long for it. So, every kid has something to work on. I don't know if there is a learning challenge your child has. You 'could' meet with a psychologist and have them tested. There is dyslexia, dyscalulia, etc. A psychologist can test for these things. ADD (not hyper) can affect kids ability to stay focused. Things can be hard. They can then avoid. A fixed mindset is a problem for a lot of kids so they don't try when it's hard. Moving them to a growth mindset can help. Motivation that is the kids is important too. What does your kiddo say when you discuss things (in a friendly way, not a YOU HAVE TO DO BETTER way)?
There is a theory of the B student. Some believe they ultimately do better in life. Could be. could be.
Your child is not on grade level when they do standardized assessments or are they?
I'm not sure from your post if you've clarified the problem. You say she appears to not be putting in the work, and is she's not putting in the work she won't obviously do well in school. Lots of students really don't like learning and so they don't really try. It's the main reason why a few excel and the rest don't as most of us are capable of doing well. As for a learning disability, does she have problems learning things she does at home? Like playing games with the family or doing puzzles at home or understanding conversations with the family or her friends? But the only way to find out for sure is to get her tested. Now, as to whether she cares or not, have you asked her? Again, her ability to think would reveal itself in everything, not just school, so again, does she have problems reading or doing things that require thought at home? If she's fine at home and understands things, if she has her hobbies and has no trouble understanding how to do them, it would suggest she doesn't like school. That's a talk you need to have with her if that's the case. Every adult on here was a kid, and we all went to school, and we all performed at different levels of accomplishment and had different levels of how much we cared about school performance. We all knew kids who wanted all As and kids who were happy with Cs. That's just the difference between people and how much they care about school and why everyone isn't at the top of the class and why you have a top of the class, it's more a matter of motivation than ability to get the grades assuming there is no learning disability.
Thank you for your comments. One more thing to add is the reason I wonder if she has a learning disability of some degree is because she still doesn’t know simple things like the order of the days of the week. Last night, we asked her “what day is after Friday?” And she said, “Monday?! I don’t know, Wednesday?” She also often gets the names of aunts and uncles mixed up, and these are people she has seen 2-4x a month her entire life. One last example, she has been taking piano lessons for 5 years and it still takes her a while to figure out notes.
Again, thanks everyone for their comments. This parenting thing is not easy and appreciate your help in figuring her (and me) out!