ghmarchica - I've quite often made the comment on this forum that testing was the best thing we have done so far (for both of our daughters). Testing really opened our eyes to an entire new world (having gifted children) and it explained a lot of things for us. It also left us with more/new questions. The testing results did help us get the ball rolling with the school so that now we have a gifted IEP for each daughter.
Private testing can be expensive so you really need to find out what it will get you. Some schools won't accept outside testing or they only accept certain tests, so you need to find out what your school policy says. What does your gifted program consist of? Is it worth fighting to get your ds into?
1st grade happened to be the year from hell for my DD also, so please feel free to look back through my older posts for additional info.
Good luck!
