I have answered this question below, however, I kept coming back to it and have added to my response as follows.  Hope this additional information is helpful to you.

Hello and thank you for writing to education.com with an important question.  Your daughter has a complex "psycho-educational" profile and that means that how she is served within her school needs to be monitored closely and frequently. I am writing the answer below under the assumption she is in a public school in the United States.

Here would be my recommendations:

First, make sure that you understand all evaluations and reports. If you don't (as they are often not written in "parent friendly" terms) then have someone explain them to you. That someone could be a school psychologist, a school parent advocate or someone else who understands these documents.

Second, ask why a 504 is requested vs. an IEP.  Frankly, if your child is struggling with her current school program, I would ask for the IEP.  But, since I don't have the reports to peruse, I would simply ask why and have it all written out for you.

Third, do not go to the meetings alone.  Bring someone else such as your spouse/significant other, friend, or a special education advocate (who should understand and help to interpret the reports for you).

Fourth, an IEP is a federal document.  504 plans are usually reserved for less serious needs within the classroom setting.  Make sure that the people at your meetings can explain clearly the difference to you.  If you were to move the IEP would "hold more weight" for transferring the accommodations ( if any) that your child has needed to be more successful within the classroom.

Lastly, anything you request needs to be in writing.  And anything that is related to your child's education needs to come to you  in writing.  Keep a file.  Make copies of all letters, etc. that you send, too.  Documentation is very, very important in special education.  Ask for two copies of every report so you can share with anyone that works with your child outside of the home (such as a pediatrician).  Send the forms yourself.  Schools sometimes get boggled down and forget (We are all human)

I am posting the National Association for School Psychologist website that has a parent section.  

Good luck and thanks again for sending an important question that I am sure will help others, too.

Regards,
Louise S.

I would work towards an IEP.  The reason is that this will carry on through High School.  By getting an IEP now, the school must commit to working towards the goals mentioned in the IEP as well as has a responsibility of taking care of educating your daughter.