Can I get in trouble for my 18 year old High School student choosing not to go school.?

It depends on the state/country and the school district's policies. Generally speaking, in most jurisdictions, parents are responsible for ensuring that their children attend school until the age of 18 or until they graduate from high school. If your child is 18 years old and enrolled in high school, it is important to make sure that they are attending school regularly. Failure to do so could result in legal consequences, including fines, jail time, or both. Additionally, your child may also face academic consequences, such as being held back or expelled. It is important to speak with your school district's truancy officer to learn about the specific policies and laws that apply in your area.