Hi there. Best of luck on your upcoming tests. I know it's scary to read here there were times when I couldn't read certain areas because it had my brain working overtime -
It's sounds pretty extensive, so likely not all of it is cancerous, though an ulceration that's been there a long time could be trouble. That's probably what they are looking at.
HPV (often tonsillar, base of tongue, throat area cancers) usually manifest in people in their 40's- 50's though nothing is written in stone. Fingers crossed its an infection of some sort. Take care.