Most vets want to spay a girl bun at 6 months or so, because they’re too tiny until then -as Dana says, at 2 months of age she would not have been spayed.
Typical puberty behaviors in a bun is pee- and poopmarking, defending territory (aka cage aggression), mood swings and also more direct sexual behaviours such as courtship (often in the form of circling the object of desire while grunting and nipping and, not rarely, peeing on it). Humping can be seen in both male and female buns. Rabbits can become quite obsessive in their courting. They have a high sex drive, because they live short lives in the wild and need to procreate as much as they can. You might be able to redirect some of these behaviors to a stuffy toy, but its common that the bun choses its human or another pet in the household as its love interest.
Girl buns should be spayed for health reasons. Some of the puberty behaviours may subside, at least to an extent, when the bun reaches adulthood, but the risk of reproductive tract disorders is still high.