There is another issue that none of the posters have touched on. I have heard from my Rebbi numerous times that the beis yaakovs do a terrible disservice to their students by having them daven the entire shachris: brachos, pesukei dizimra, birchos krias shema, shema, shemoneh esrei, etc. He said that the reason so many married women use “taking care of children” as a hetter to not daven is because they think they need 45 minutes to daven, when in reality all they need is 5 min to daven shemoneh esrei. There is a chiyuv for women to daven, anywhere between 1 and 3 tefillos a day depending on which shittah, and that chiyuv is unfortunately neglected by manny married women who feel that they don’t have the time. I would imagine that my Rebbi would say the same thing about a girl who takes an hr for shemoneh esrei.
As a side point about girls saying brichos k’s, from my own personal experience it seems that many women daven after zman tefillah, in which case it is assur to say birchos k’s, and they should be aware of that (as should the men who wake up late).