Sounds like a stupid question but for me it took a couple of days after my ds was born. I had a long labour with him so dont remember much of it, then he was taken to the NICU for his first night. It wasnt until the next day that i actually got to be alone with him and have proper cuddles and to be honest i was terrified i had no clue what i was doing.lol
The moment that i actually felt like his mummy was when i got visitors the next day, a friend of mine was holding him and he started to really scream and she said oh you had better go back to mummy and handed him straight to me and that was when it actually clicked that I was his mum. I remember that moment so clearly even today 8 years later. I didnt have that with my other children just my first. It was very strange that that simple moment made it all seem real.