Hello @brad78 and welcome to our group. I was around your age when I went through a similar bout with SSC. My daughter was about eleven at the time. About four weeks into radiation, she tucked me into bed and read Harry Potter chapters to me.
You wouldn't be normal if you were not scared. Your life is meeting one of those big life events and the unknown is overwhelming at times. Fortunately there have been many advances in the treatments of Head and Neck Cancer, particularly with HPV16+ type where the success rates have soared. As long as your doctors and radiologist have previous experience with SSC, you should have little to worry about other than the treatment and healing trip you are about to enjoy.
Two tips for now. One, you might inquire about a feeding tube as you may have difficulty to eat temporarily, and two, you may find it difficult if not impossible to work for the last ten radiotherapy treatments and for about two or three weeks afterwards. In fact it will take many months if not years to get to your new normal.
But hey, my daughter is all grown up now and I'm living the crazy life. You can do this.
Reach out to me or anyone in this group if you have questions. We often have more experience than the physicians who often have no experience from the patient's point of view. Courage.