Try not to worry about it being a sign of future problems. It's a phase, and a very common one. I am not even sure that you can do much to modify the behaviour... She will grow out of it as her brain and language mature and she becomes more aware of others, and the effects she can have. Margin Sutherland book 'science of pArenting' is very useful to understand how a chid's brain develops and what can be expected. It sounds like your daughter will Always be lively and assertive - that doesn't mEan she will carry on being violent, once she leaves toddlerhood behind.