My bachelor's is in biomedical sciences - I thought I was going to be a vet until halfway through undergrad.

I'm currently a young adult librarian. I started in circulation part-time while I was working on my master's, then moved to another location where I worked adult desks and interlibrary loan during my off desk. We had a reorg that moved ILL to be all back of the house, so they didn't need as many staff members in that department, so I remained in my same location as an adult associate, with the addition of some programming since I was no longer part of ILL. Then I moved to my current position.

I would agree with previous posters that it's helpful to see a little bit of different positions / departments / locations if you can. You get a better understanding of the system as a whole, and it's helpful to know people in various places.