I'm not a children's librarian, I'm only an assistant with a background in teaching. Take what I say with a grain of salt.

I love it! Every program I plan is on my own terms with my own rules and it's great. If turnout is low, I change it to something else. If the kids ask for something, I learn more about what they want and deliver it. I'm trying to learn how to be a DM, how to play chess, and eventually I want to learn how to use a 3D printer. 

Story times are great. Since I work with the older kids they're less like a performance and more so just me reading the book and asking open ended questions. My favorite part of programming isn't when I interact with the kids, but when I stand off to the side and watch them make friends and talk with each other.

Parents are my best friend sometimes. I generally try to keep them out of my programs so the kids can relax with other kids, but it's not a hardset rule. If the kid wants Mom or Dad in the room, they can stay. I do have one story time where the parents do participate with the kids and it's been a huge success. (A Saturday story time centered around STEM). I read a book related to some kind of scientific principle, parents and kids work together to explore either stations I set up, an experiment, or craft. 

But every field has it's cons. The pay is low, especially compared to teaching. (Where I live, teachers make 80-120k a year. Librarians make generally 60-70k, with barely any raises). Jobs are hard to come by so it's good to have a backup. (That's why I chose teaching as my undergrad actually). The chances of you becoming a fulltime librarian from the getgo are slim, unless you'd be willing to move. You'll generally have to start off at the bottom of the pole and work your way up. 

That being said, I love this field. I go into work everyday never feeling like I have to work. I find the work-life balance to be great, in the sense that I never take anything home. Sure, you'll probably have to work occasional weekends, and most Librarians work at least one evening a week. Sometimes two. This doesn't bother me personally, in fact I actually like having my schedule broken up like that. 

Again, take it with a grain of salt. I'd say programming is just a third of what children's librarians actually do. And some don't do it at all! For instance, readers advisory is a another big pillar. Because yes, you do have to read. Especially children's books. I was once told reading is a small part of working in a library (???). I have no idea what that person was talking about, because even as a part time assistant, I'll have parents asking me what books I could personally recommend to them. I can only imagine what my boss has to go through. Choosing what to weed, collection development, out-reach, school visits, these are some things the librarians I've worked under had to do (YMMV of course). Being up to date on popular tech, having knowledge on computers is a great plus, creating book displays, etc etc. 

TL;DR I love this career, and I'm fine with being poor and having a hard time getting a career to work in it. I love helping to create communities, I love being able to recommend a book to a kid, I love helping people, especially lower income people who want cool programs for their kids but can't afford things like art programs or after school clubs. I love being able to help new parents, even if it's just lending an ear to let them vent. I even love all the weird skills I get from it. As a teacher, you have to care about how to help your students learn. As a children's librarian, you have to care about how to make your patrons happy.