Muslims, i need help here.?

alamu-alaikum Now i know i shouldn't be asking this on Y!A but right now this is the only place i can go. Okay, so, our community's Imam is sick an out of town this week so he will not be able to give the Khutbah next friday at our Masjid. And out of nowhere the people turned to me, they want me to give the Khutbah. Now, i've always dreamed of that, but i always thought it'd happen when i was much older. Right now i am only 16. i just graduated from high school (alhamdulillah) and am a very studious person in this deen. But i don't consider myself ready to be an Imam yet. I wouldn't know what to teach them, and then there's the pressure. I mean one wrong thing and i've got the sin for misguiding so many others. I know they're not unlearned or ignorant so someone is bound to catch my mistakes, but what about those that don't know i may be wrong? And also, i'm not good at public speaking yet. I still got terrified every time i gave a speech at school. So how can i overcome this, what can i give the khutbah on, and any extra help you can give to a young Muslim brother about to give his first khutbah would be nice. alamu-alaikum warahmatullahi wabarakatu