Is it a bad idea to send birth announcements while my baby is still in the nursery?

When you find time! Birth announcements are wonderful to send any time after the baby's birth. But, don't stress about getting them out at any certain time; you'll have enough to do for the first few weeks. Send them whenever you feel comfortable and don't feel like you must stress yourself additionally to get them out at some predetermined time.
The joy of birth. Labor is traumatic for mother and child, and a few babies, and mothers will have complications. You should give thanks and express your joy with the miracle of birth, whenever you have the energy and desire.