Quoting Rain (aka Mama):" It's not just about fairness, but that I think they should each be treated equally. She already does ... [snip!] ... really commented the other concern, that she can't go through a speech session on her own yet (which is only 30-45 minutes). "
I can't even tell you the huge difference it made for my son being in school vs therapy. It was amazing, he went from almost completely non verbal to communicating directly in just a few weeks. He now goes to a full day and speaks in 3-4 word sentences just since Sept. School will open so much to her.
As for the rest the teachers are trained to deal with these types of situations. Talk with them before she starts and see if you can sit in for the first hour for a few days. In the mean time try taking small breaks away from her during speech. Tell her you have to go potty and she needs to stay there.