“If I’m 17 years old do I have to go with an 18 year old to see if I have any kind of STD?”
In most states, testing and treatment for STDs does not require an adult, particularly if you have Medicaid. I would suggest that you either seek care at the Health Department or ask you provider if your care is confidential. If your provider says they will contact your parents, find a provider that offers youth friendly services and will keep your visit confidential.