My DS was 19 months and had to come to the hossy with us as I went into labour early and it was fast. A friend came to pick him up but the baby was born a few minutes later and I really wish we'd had him stay to watch. However, for a normal labour which takes a bit longer, I would think you'd need an extra support person - either for you or your DD. If your DD takes all your DH's time there'll be no one for you.