I'm a Hannah and I don't like it (sorry!) There are loads of us about and there aren't really any nicknames so you just end up being Hannah C or whatever. It's also very 80s/90s, though at least that means she might be the only one in her class. I DO like that it's a palindrome and easy to spell/learn to write!
Tbh Kate is a bit boring too but something like Catherine would give more options.