The first time one of my adults left, I was sad, but you go on to the next generation, and it lets you know you took good care of it long enough for it to have a kid.
Based what happend with my 1G boy and with one of my friend's girl tamagotchi had babies and it tooked 3 days for her to leave and it tooked my boy tamagotchi 2 days so I guessing your tamagotchi is a girl Hstama?