Congratulations. 
I have two boys, (8 and 10 years) and a 3 year old dd.
When I found out I was expecting dd I panicked. I remember thinking 'but I won't know what to do with a girl'.
Mind you, I vaguely remember thinking the opposite when I was expecting ds1, as I had no experience of little boys back then, as I'd only really known my two nieces and younger sister.
Of course it was a daft thing to think, dd is my baby, just like the other two. She loves Thomas the Tank Engine and Fireman Sam, but also Peppa Pig, Ben and Holly, fairies and 'pink/sparkly things'. She is a fantastic mix - the best of both worlds. 
All three of mine are lovely, regardless of gender. The boys are funny, chaotic, energetic, affectionate and loving and dd is a whirlwind of chatter, noise, mess and laughter with lovely cuddles thrown in for good measure.
Most of all they are each total individuals, with none of them remotely like the others and that's the important part to remember.
Ds1 bores my ears off with endless talk of Pokemon and Star Wars, loves anything mathematical or scientific and gives lovely bony hugs. Ds2 is quiet, cuddly, artistic, generous of spirit and amazingly patient, kind and helpful with his little sister (he wants to be an infant school teacher
).
Dd is the bossiest and noisiest of the lot. She loves to cuddle up and read mountains of books with me in one sitting, she likes to bake cakes for her brothers' after school treats, she always asks for a Barbie when the adverts come on the television (the answer is always no by the way, although I am fairly resigned to having to give in at some point now she's started school) and adores her jewellery box and fairy dressing up outfit. Yet she can sword fight and play Pokemon as well as any 8 year old boy! 
I know people often say 'a son's a son 'til he get's a wife, but a daughter's a daughter for life', but personally I think that's more down to individual families and their relationships than being 'typical'. Dh isn't close with his mum, but then that's because of the relationships within his family, rather than because he expected me to take on her role once we got together. I do think lots of girls end up being closer to their mum when they have their own children, even if they haven't been all that close before, as obviously they want/need the support and also start to recognise a whole new perspective on the mother daughter relationship. Again though, this is by no means universal and I know plenty of women who are closer to their MIL's than there mothers.