I worked in my school library in grade school (up to age 12) and high school (age 13-17). I just wanted to be around books but didn't consider it as a career. However, nothing else presented itself over the years and by the time I was 23, graduated with a BA and out working in the real world, I was seriously looking for a career, not a job.
Librarianship was a fall back career but it was the right one.
I studied to be a children's librarian at a school that actually had professors teaching that subject. Now, I understand, it is more difficult to find.
Approximately 16 years pass, then about 12 years ago, my library was jumping on the bandwagon and creating a website and anyone in the library system who was interested, could participate. I was one of the few who were committed enough to work hard and learn what was needed and this led to me being recommended by one of the directors as the perfect person to work on a much bigger project.
Since then I am one of the few librarians who have a dual specialty in children's and web work. I spend about 75% of my time working on the children's website for our public library.
I don't work with children anymore except in a branch on Sundays. This helps to keep me grounded and aware of what kids are doing these days.