We have an older bun - Gorgeous George. We don't know exactly how old he is, but he is no spring chicken. He has no front teeth and is a bit boney, but so loving. Out of all our buns he's the one who loves a cuddle.
We have one very young bun who came from a rescue, she is a Belgian Hare and no-one wanted her because she wasn't fluffy. She's a bit of a handful but very very cute.
Our others (10 in total) range from 1-4 or 5, with George being an unknown age, but I would never reject a bunny on age simply because the older ones are (sometimes) calmer and more socialable.