At loss with my child. I need some advice!!!

I don’t even know how to put this in words. We have a 7 year old in 2nd grade. My husband and I are both immigrants in US and have not studied here so we don’t know what to do. My daughter has been a stubborn, highly sensitive kid from the beginning. She has been defiant and we have tried many ways to help guide her and bring discipline. As she has developed, some days/months have been better than before. She thrives on positive reinforcement and we have tried to provide that in many ways. One thing has been consistent and she not following directions and rules in school or home and questioning everything. We explain why, be strict, have given good/bad consequences but it’s been hit and miss and very slow progress. Her anger issues has also risen. She used to shut down a lot but she has gotten so much better at expressing and has been more vocal. We have been partnering with school and things have been going ok. In second grade, the teacher has been a little more strict and overwhelmed by the kids so she doesn’t have as much patience with my daughter. We kept reinforcing rules and telling teacher we have been working with her. Today I got a call from principal that she didn’t follow instructions and come off the edge of the field where she wasn’t supposed to go. They asked her a few times and she didn’t listen (when I asked her why once she was back, she told me a friend upset her and she got mad so she stayed where she was) and shut down when they talked to her. Principal told me it’s a safety concern and that he wants to meet with me next week. So I am going to meet him next week. I am scared what this means. Please help. I also don’t know what it means to be written up as he said that he did that. I am at loss. My husband and I are going to reach out for outside help and get her into counseling but knowing it’s not going to get magically better and will take time and she will need patience, I don’t know what to tell the principal. What are the consequences?