Welcome to the forum :biggrin:
As Karen said, rabbits are individuals. What happened after sterilization differs for each rabbit.
My Donut (5 months turning 6 months) who used to be the most sociable lil guy in the world, suddenly became wary and is now terrified of human contact.
Cookie (Donut's brother, also turning 6 months) however, suddenly became nicer towards me. He used to run away when he sees me approaching but now he'll stay where he is and let me pet him.
Chestnut (4 years) was neutered when he turned 7months. I don't know what he was like prior to living with me (he's a rescue) but his previous owners said he used to be really nasty and tearing furniture apart. Now all I know is that he's the loveliest amongst the trio and my personal favourite. He comes up to me for pets and loves it when I hug him :]
Long story short, sterilization isn't a bad thing. In fact, rabbits are more prone to diseases and cancers if they're not sterilized. Whatever the outcome is, you're a good person and I'm sure your rabbits will appreciate what you do for them
all the best with your lovely girl an tell us how to goes :biggrin: x