Dear Ms Carter,
I would like to apply for the position of a babysitter which I saw advertised in the Internet.
One of my reasons for applying is that I love children and I am sure that I am a perfect man for this job.
I am twenty-two years old and at present I am majoring in childhood education. I enjoy working with children very much and they are my whole world.
I feel I would be well-suited for it because I am a young man, I have two younger brothers and I know perfectly well how to take care of children and in the near future I am going to be a teacher. This job would give me the opportunity to get further work experience.
I am available to come for an interview at any time convenient for you.
I hope my application will be taken into consideration.