Very cool about your job. Being a happy mother and role model is always a good start for raising daughters, as is wanting to be tuned in and supportive.
Some of the best advice I've read on communication was in Parenting A Gifted Child, by James Webb, et al, so I will quote a few nuggets.
"You can't force your child to communicate with you... change your thinking to "How can I encourage my child to want to communicate with me?" You must not expect instant total communication. The more you push, the more she will retreat. Privacy is a legitimate need of adolescents too. Reading about adolescence, if you haven't already, will help remind you why she is moody and that it may not mean a big problem is going on. You can leave these books out where she can find them so whe might borrow them, if she's curious. We've had discussions about adolescence in our house so that our kids understand it's just a time of mood swings, and they will grow of if it, just as they grew into it. So, we will try to give them space and support while it is going on, and they should cut themselves some slack too. Our son changed almost over night into a more moody child - it was a crack up. His sister is observing this textbook case of adolescence, thinking it won't happen to her, but it will!
Tips to fostering communication include 1) recognize and express authentic feelings yourself, including negative feelings (sounds like you do.)
2) Check in re: how we are being perceived by our children. This is also something we talk about openly in our house and I make adjustments to how I communicate, based on my kids feedback, even if I think they are overreacting, because people's needs for support not necessarily a rational thing. This builds our relationship too. Perhaps your daughter is feeling your support and that's enough. Perhaps "expectant praise" might feel best to her, acknowleding the big changes she's going through, how proud you are of her coping with these transitions, and explore how if she is feeling your support and/or if there is anything else you can do for her because you love her. Spending quality time together, even if she is not sharing feeligs, might mean a lot to her.
The mood swings are going to be there -- perhaps you're doing a better job than you think! Maybe what it is is that she's an adolescent, and your son is not. My son's relationship with me changed when he hit adolescence and I'm realizing it's not personal. We're still close, it's just different now.
Good luck,
D.