I think she would want the best for you. If getting another bunny makes you happy then I would do it. Loss is hard but the time we have with them is so worth it. They are total blessings in our lives.
I was scared about getting my bun neutered too. He is my first rabbit ever. But I got it done. He did really well. I don't know if that helps you feel better about it or not. But just wanted to say I understand the fear of it.
Feeding Timothy hay now makes it easier because otherwise you have to transition from alfalfa when they are 6 months. Some rabbits don't like to transition.
It's ok to give young rabbits Timothy hay as long as they have alfalfa based pellets.
You just need to fully feed Timothy pellets and Timothy hay for 6 months and up.
Do you use oxbow essentials young rabbit? If you do it is made of alfalfa. So you can feed Timothy instead of alfalfa hay. I did that with my bunny when he was little. It works great!