I am the Mother of 2 girls, 1 is a minor, 1 is not.. We recently inherited land from my mother's estate, in "equal shares". My oldest daughter and I do not get along at all. She is saying I can not build a home on the land without her say so, that I can not even go onto the property without her say so. What rights do I have with my minor's share and my share?

She can certainly prevent you from building on the property, but she can't prevent you from entering the property. As co-owners you have to agree on any improvement. But as co owners you are entitled to equal access.

ScottGem is correct insofar as access is concerned; I don't know if a co-owner actually need's the consent of all to build. But in my opinion co-ownership is a very poor idea in most cases. Was the probate process concluded? If so, what you could do would be go to court to "partition" the property. That would normally result in a court-ordered sale, with each of your daughters getting 1/3 of the proceeds.