“I’m pretty sure I have a tic disorder?”

A neurologist might be able to help you. Most doctors will be able to work with you and not involve your family, if that is what you wish.

It seems you are finishing your adolescence and starting to make your life matter decisions, and that is good. You are in the middle of it now. If I were about your age I would start with a pediatric consult. He or she will give you at the beginning the answers to your questions, how your body is working and how mind and body interacts. After your first visit, you can start asking your pediatrician some help to manage you independently from your mother. Just for some visits to see what happens. A good pediatrician can manage wisely at the beginning.

Have neurology see you in free environment.

I'm very sorry that your mother is being so unsupportive. You probably do indeed have a tic disorder. Whereas the age of onset of tics is most commonly in childhood in boys, it is commonly a bit later in females and onset in adolescence is not that unusual. Be assured that your mother cannot have you admitted to a psychiatric institution against your will. This could only be done by two psychiatrists who are in agreement that your were suffering from a severe psychiatric condition that made this absolutely necessary and that would never be considered with a simple tic disorder. I would definitely bring the condition up with your primary care doctor. Hopefully he will recognize it as a tic disorder and, if he is not particularly comfortable managing this himself (many primary care doctors are not), he may well refer you to a neurologist, which I would hope would happen. The treatments for tics include both medications and cognitive-behavioral therapy (CBIT), but this depends on how much the tics are interfering with everyday life and sometimes education about the disorder is all that is needed. Sometimes there are associated conditions, including obsessive-compulsive symptoms or other forms of anxiety, which might also need to be addressed.

See this link first
https://tourette.org/about-tourette/overview/living-tourette-syndrome/teens-13-17/
After reviewing this link, make an appointment with doctor and let his staff know ahead of time, that you desire to see him w/o your mom at first. Once you and doctor have reviewed your case, then involve your mom.

You definitely need to be evaluated by a professional to rule out tic disorder. As far as I know, there isn’t any jurisdiction where patients with tic disorder need to be admitted to hospital.