We also do whatever we can to enable her to participate in what we are doing (sadly computers are a big problem in that regard, much more than say chopping with a knife). Our kid is very well-behaved and cautious (except for tired/hungry breakdowns, of course).
I am also a big believer in the see-what happens school of action. Other parents are always encouraging (yelling at) their kids to share, particularly in support of aggressive children trying to take from their child. We believe in letting children experiment and realize that sharing leads to fun, greediness not so much. We demonstrate the power of choosing not to play others which is really the best way of handling unpleasant people/situations.
But at the heart of it all is simply being, authentically, the kind of person you want your child to be. They are programmed to learn actual behavior from their parents who 1) have been successful enough to reproduce and 2) have a similar genetic makeup meaning their behaviors are likely to be compatible with the kid's abilities.
So be a better person and relax. Oh, and look into Sudbury education for your kids which really teaches them how to be moral in a community.