Lightuptheworld:
I didn’t see your post when I wrote mine – in fact looking at the time stamp, mine was actually first. The Maharsha explains that the reason why it’s good to have a daughter first is that then there will be no bechor and therefore no one will get a larger share of the inheritance. When there is a bechor, the other sons will be jealous and they might cause an ayin hara.
R’ Menashe Klein says a similar pshat (Shu”t Mishneh Halachos 10:13) – that not having a bechor is good because everyone is equal as opposed to if there is a bechor, there is a chiyuv of kibud for him. (It’s interesting that he doesn’t quote the Maharsha since he is giving the same structural explanation with just a different reason for why it’s good.)