Jo - if it were me, I'd mix it up. Technically, when you open the door you are asking your pup to go outside. By waiting, the command has become a grey area. She will go, but when she's ready.
So I think sometimes I'd make her go out and sometimes I'd let her wait. So she'd think I'm still in charge. It's all about keeping them confused that keeps us in the driver's seat.
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar - Texas Blue Lacy
Funyon, Ashe, Soot - Barn Cats
Scooter /1/2 Arabian, Shadow, Katie / APHA