Is it possible for me to take her and get her transcripts somehow with out my moms consent?
If your sister is 18 years old, she is an adult.
She has already arrived at the age of majority.
She can vote, should she wish to do so.
She can disenroll herself from the high school.
She no longer needs her parental units' permission to do anything.
She can request copies of her school records.
She can even complete high school by simply taking any approved GED course.
She can enroll into any community college without graduating from a high school, should she wish to do so.
She can move anywhere on the planet if she has the MONEY to get there, including Nebraska.
She can enroll herself in a high school in Nebraska, should she so desire.
If you and she want to get, you can start getting tonight.
Safe travels, and remember to make smart choices.
Each of you now have your life under your control.
From this point forward, other than obeying the laws of our land, you and she can do something or nothing.
You are now the boss of you.