I honestly think this is a case of each to their own, as you know your DD (or other posters, their children) and know whether or not your DD would be comfortable and ok to be at your birth. For me, I didn't consider having my boys (then 4.5 and nearly 3) present. Not sure if it's their gender, but they'd be into "stuff" and generally on-the-go. So for me, it would be distracting. I've had amazing births, but it's been down to my ability to focus 110pc on me and what my body is doing. I couldn't get in to that headspace if I had distractions. Mind you, I had hospital births and only had DH as my birth support. I'd imagine that if I were at home and/or with a few other support people to look after my child and distract them as needed, then I may feel differently.

But ultimately, you know your DD and if you feel good about having her there, and that she'd be fine to be there during labour and when her little "sister" is born, then why not