Two things to think about:
Firstly, if she has been to a school with boys and maybe had a brother then fine. As she knows what boys are about and how to behave with them, and how they behave.
Many kids at girls schools only have sisters (many, not all, before anyone jumps on me) because people usually want to send their kids to the same school, so if you have a boy you’re more likely to send them mixed - so therefore you really aren’t around many boys at all growing up if you go from primary age. To cut off half the world’s population like this (iyswim) can make it a hard adjustment when you’re at college and suddenly you’re expected to know how to interact with boys but you’ve never been around them in an every day capacity.
for me and many of my friends our first time meeting boys were when we were older teens getting our first taste of freedom. This meant our first encounter with boys was during that phase where you’re flirting and “who likes who”. Then when we went to college we didn’t know how to behave ‘normally’. We were used to being dressed up to meet guys out. Putting on a front and only letting them see us when we looked ‘perfect’ and done up. Not being next to them studying. It was uncomfortable. Now I have mainly male friends and a male partner and a son so I have clearly got over this but it did cause issues. For example lots of us felt uncomfortable eating in front of boys (?!) when we first came into the mixed world. We would awkwardly flirt and generally just feel foolish and not know how to speak to boys. Oh and don’t get me started about being expected to do sports in front of boys! That was the cringiest thing ever. Ever.
Secondly, if your daughter is good at what this particular school wants…that is to say if she will fit snugly into their mould….she will do great. If she bucks against authority in any way, if she is opinionated, if she isn’t academic but the school is, I would reconsider.
If they want to churn out rocket scientists and engineers but she loves drama and sport, then no. Don’t even bother. The kids that don’t do what they want wreck what they’re striving for as a business - remember their appearance is everything as they need people to part with their money, and they get them to do so by buying into the school. Parents won’t buy into the school if the school is underperforming- thus not leaving much room for individuality or experimentation (no matter what their marketing says)
Your child is exempt if she’s the “golden girl” type - academic and able to also produce good work in the arts/sports/music field - then definitely send her and she’ll get her artwork displayed in the school foyer every open day and every lead in the plays
Now for fair opportunity’s sake I’m happy to list the pros:
Good basic level of education - taught how to write constructive and persuasive essays. Which will do her well at uni/in her career.
Teaches, through example and peer pressure, the expectation of a high standard of work. Again good for career.
I want to say that it allows them to stay young for longer but I don’t know how this has changed. I’m not that old but I’m not young enough to have been at school with the TikTok brigade.
If she is suited to the school, the smaller class sizes allow more individual attention.
Although on the other hand, less friends to choose from (if you get selected as a bully’s target then where are you going to go when there’s hardly anybody else to pick from).
The other parents tend to all be pulling in the same direction - this would be my biggest positive. You’ll find the majority of them are similar in their desires and wishes for their children’s futures (this does not necessarily mean their values fyi). This is good because if there’s an issue (I.e. smoking or drinking or whatever) usually the parents are in agreement on whether to tackle it or not.
Either way, you’re already doing great by her by weighing it all up, and if she goes somewhere and doesn’t get on she can always switch schools.