Not only am I a mother, I have 3 younger brothers who I have watched since I was 12 years old. Two are 12, and one is 9. My parents both worked full time jobs, so in the summer, it was just me and them. I would make breakfast and lunch, change diapers, read them books, play board games with them, play outside, and sometimes even have a picnic. My family would call me their second mom. And to this day, I still am asked to watch them (pretty frequently).
I have also held a full time nanny position. I worked for about 6 months for a couple in Mebane NC. I had to stop working because I enrolled in college, and could not do full time anymore. At that job, I took care of (at the start) a 3 month old girl, my daughter, who was 6 months, and a 5 year old girl. I would make bottles, change diapers, put them down for naps, read them books, play in the playroom, take them on walks to the park, all the normal things you would do with babies. The father worked from home most days, and so in the beginning he would occasionally let me know what the baby liked, which helped a lot! After a while though, I started learning about her and it became much easier for both of us.