I voted no only because there's no option for it depends.

Frankly, suicidal thoughts are relatively frequent for 18 year olds and they're usually not as serious as someone in later life.
A hospital would likely just give you meds and that could make things worse.

Although, maybe your are serious and maybe you need meds. You need to
make that judgement. Although I'm guessing your instinct about hospitals is a good one.

Perhaps you could ask your therapist, hypothetically, if he/she would send you to a hospital against your will. In some states they can. If your therapist
doesn't give a definite direct answer, find a different therapist.