I told her I was her mama and that I just knew and that I would love her unconditionally.
She said she still liked both guys and girls, but she definitely liked the 17 year old and she couldn't help her feelings. Fast forward two weeks- we've told dad which was hard but he is supportive (ish) it's still new.
Let her know you're there to talk if she needs you, but that you're not going to insist she open her own thought processes to you if she's not ready to do so.
I am not really understanding why you had to tear them apart.
I’m assuming you are based in the USA, in which case you might like to check out Wikipedia’s page concerning the age of consent in whichever of the 50 states you reside in: I hope my comments have been at least somewhat useful. The maturity level between 13 and 17 is so vast and I'm very glad the other girl agreed to back off rather than messing with your daughter's emotions; she sounds like she'll be a good friend down the road, once the dust has a chance to settle.
If you don't listen to Dan Savage's podcast, I'd recommend it, for your own sanity if nothing else.
Anyhow, my daughter has finally found her "soul mate" friends (she says) that really understand her and has been texting them (2 in particular) at all hours. I am very close with my daughter and started seeing something "more" going with her feelings wise for the 17 year old who played her opposite as the lead in the past play, where they also shared a kissing scene, multiple times.
Well, I met with the 17yo, (who insisted they were friends) explained they were not allowed to see each other anymore, and thank goodness the 17yo obliged.
(There are a couple of points I would have liked a little clarification on: for instance, the wording of your description about how your husband was informed about your daughter's lesbian crush made me wonder if you are actually divorced and living in separate households, which would presumably make it more difficult to coordinate the way you handle some of the issues that are liable to arise in connection with your daughter’s upbringing.) Regardless, it does seem clear that there was a considerable failure (or several failures) of communication along the way.
It seems important for healthy communication channels between all the members of your family to be reestablished as soon as is reasonably possible in order to restore a more normal atmosphere, and of course to improve the frayed relations between your daughter and yourselves.
I'd also recommend trying to spend some 'normal' time with her, if you can.
Go do one-on-one normal things and let her process this at her own speed.