You are correct the age of consent is 16 in Indiana. However, "The age limit rises to 18, according to IC35-42-4-7, if the actor is an adult who is the guardian, adoptive parent, adoptive grandparent, custodian, or stepparent of the minor; or a child care worker for the minor; or a military recruiter who is attempting to enlist over the minor." It also depends on what the mother will be accusing you of to have you arrested. You may wish to consult with a local attorney to cover all your bases.
Regardless of the age of consent, parents have the right to disapprove of their minor children's friendships and activities. They can forbid their daughter to associate with you, and can potentially obtain a restraining order.