I believe she was talking about former Brownies. She looked at the girls when they were little and thought which one would be the first one to get pregnant. When the daughter says another Brownie got pregnant she's referring to the girls that she was in the Brownies with.
Oh! (Embarrassed.) Of course you're right. She's talking about "what happened to these Brownies in just a few years." If I'd re-read I would have realized that.