G.♣.
Our son is in 3rd grade, but he turned 9 in July. He did an extra year of PreK, and was 6 when he started kindergarten. Best thing we could have done for him.
I talked to lots of mom's about their experiences when we were still trying to decide. One mom was in a similar place as you. Their daughter was struggling in 2nd or 3rd grade, and they decided to have her repeat the grade. They were very nervous about how she would do and how she would handle it. It had been a couple of years since she had repeated the grade, and the mom said she had no regrets. Her daughter fit in so much better with her peers, and she was doing really well in school.
Talk to the teacher and maybe the school counselor or social worker. Maybe the counselor or social worker can come in and observe her and take some notes. Just see what can be done to get a better overall picture of the situation. You might find that she really needs to be in 3rd grade Shan next year. You could also find that she is struggling but is also making progress. Maybe extra tutoring over the summer will help. Maybe she needs to be with the kids currently in 2nd grade. Ask lots of questions and keep mulling it over. I think, in time, you'll know what's right for your daughter.
Keep in mind that there are kids in her class that are almost a full year Oder than her. That is a big deal at her age.
There really are many success stories of children repeatng a year, as long as it's done with the right attitude.