This young lionhead can change a lot, if she's 2-3 months old now she's still like a baby and depending on her personal development she can start becoming hormonal between 5 and 8 months, so she can change a lot, you basically don't know if she will stay calm and sweet.
You do what you think is right for you but since it's your first experience with rabbits I would go with just one adult fixed female and if you want a friend for her I'd be looking at neutered males older than 6 months or even older, and neutered more than 2-3 months ago.
In your situation they never met each other I would say it can be risky. If you decided to take both maybe you can arrange their date there where they are now so you can see how they react to each other. But with the young one as I said already she will grow and she will change. After 1 year old she will be more stable, but for now she has her teenage phase ahead.