Odd question I know, but I'm worrying she may have got an infection, but also would feel a bit of an idiot if I took her to the doctors to find out it's normal...
... so Mumsnet to the rescue please! 
It's not an overpowering smell, one I would consider normal for a grown up woman but fainter - but she's not grown up and for some reason I wouldn't expect a smell!
I smell it mainly when she's been scratching herself then the smell is on her fingers - and the scratching is also why I'm a bit worried it might be an infection... except she also has eczema around the labia and thighs which might be causing the scratching - or it might be just because she likes to scratch! I have her nappy off a lot because of the eczema as welll...