US Immigration from Jamaica

I am currently inside the US and I have been since being petitioned.

My father petitioned me and my younger brother, we did all the paperwork ourselves. All the forms filed were : I130, I485, I765, I864. Forms I130 were filed first, then the others some months after . I did research during the initial filing stage and saw the forms could be concurrently filed, which is what I did for me and my brother (I handled all paperwork and filing for us both, while father paid the fees).

Since then, my brother and I got our ssn and work permit. Recently , we both got updates from USCIS, my brother's requested his medical but mine has the medical request and this RFE . It says I have until April 24th to respond and I'm worried I might have messed up my application somewhere, because I honestly don't know what to give them.

Ever since getting the RFE I've been doing more research and here is where I could have went wrong:

• My green card application I485 was filed before getting I130 approval, unlike my brother who did have an approval letter when I mailed our applications (I mailed my receipt of I130 instead to show case was pending). However, my I130 petition was approved.
• Possibly Ineligible for concurrent filing; because of my age/category I could have been ineligible unlike my brother who was a month before 21 when I sent in our paperwork.

If anyone can point out where I went wrong and explain the letter that would be really helpful so I can better prepare for my consultation.