I would have been OK with a mix. However, my first choice would be just girls (which I have.)
Never wanted just boys. Hard to explain why. I just never saw myself as a boy mum. Nothing against boys, some boys are lovely children, and some girls can be a PITA! I know several families with a boy and a girl and the boy is the more likeable child! I just didn't want to be a boy mum. (Lots of girls are lovely by the way!)
I have to say, I have always had a good relationship with both of my girls, and still do now (they're in their early 30s,) and they were stereotypical girls growing up (Barbie, everything pink, dollhouses, teddies, ponies, Disney, pop music, kittens, singing and dancing, theatre etc.) They are both in successful careers now and both have their own place with their partner(s.) Both lovely, beautiful, kind young women.
No guarantee that girls will be what you want/expect, but mine were. (Would have been OK if they hadn't have been by the way!)
It's just that I have zero interest in things boys often seem to be into - like golf, football, rugby, ice hockey, basketball, fishing, skateboarding, martial arts, cycling, etc etc... I couldn't imagine trudging out of an evening to stand in a sports stadium or a muddy field in the cold and rain. I know some boy mums who spend half their waking hours following their son(s) and his/their football, sitting on the edges of the fields in the dark, and they almost all hate it!
I know there is no guarantee that a girl won't be into these stereotypical boy pursuits, but let's face it, they are less likely to be!
DH wanted girls too as he hates sports and most outdoor activities! And he just never saw himself with sons.. He was as thrilled as me when we had 2 girls. He did used to like and play videogames though, and got both our girls into them. (He stopped playing when they were about 8-10, so when he was about 40.) I have always enjoyed videogames too, especially platform games. Oh, and all 4 of us (DH and I, and our 2 DDs,) are interested in transport, (cars, planes, trains, ships, helicopters, motorbikes you name it!) DH and I got this from our dads, and our DDs got it from us. Don't do much transport related hobbies, but just all have an interest...
I know a number of men who were thrilled when they had daughters. It's a myth that all men want sons. Maybe in certain cultures, but many men I know were very happy to have girls! Would have been happy with boys (but were fine with just girls.) My uncle had 4 daughters, and he has always adored 'his girls.'
There also the fact (even though some won't admit it) that girls stay closer to the mum/parents. I (and DH) do actually meet up with/socialise with our DDs much more often than the boy mums I know meet up with their sons. I mean, a few do, but not many, and not often. Many people I know see their adult daughters much more often than people see their adult sons.