1. For selling minors' property, you have to obtain competent Court's permission to sell the property and the proceeds has to be used for minor children's welfare like education, hostel facilities, foreign study, etc. Even if you mention regarding selling of the land before your children attaining majority in the Gift Deed, it will not be legally valid.
2. If your parents execute a WILL bequeathing the property to you only ,then after their death you will inherit their property. However, if your parents die intestate ( without executing a WILL ), then their properties would devolve equally to you and your siblings. In the instant case, you and your two elder sisters will be entitled to, i.e., 1/3rd share each. If your two sisters' execute a registered Release Deed relinquishing their rights over the property in your favour, then you will become the sole owner of the property. Or
3. Your parents, during their lifetime itself, can execute a registered Gift Deed in your favour, then you will become owner of the property, without any issues from your sister's.