You poor thing. You will hit many bumps in the road along the way and this is just the start. The best thing to do is to go to the principal and speak to them. HOWEVER, first let the teacher know that that is what you would like to do and you you would like to have a conference with all 3 of them to discuss your concerns. You may want to speak about classroom differentiation. You do not want to throw your child's teacher under the bus but you also can not let her dictate his whole year because otherwise it will be a whole year wasted (which we have all have happened). However, if the principal is not going to be willing to help then got to the next person in charge (administration). I just hope that they are willing to work with you.