Same age. Dude, you're not gross and there's no weird reason. Most people haven't done anything sexual at 18, don't put yourself under pressure. I know your 5 siblings are talking big and all, but really what you're experiencing is nothing out of the ordinary.
You say you're worried about 'seducing'? It comes naturally, there's no need to consciously choose to do that, or it's just awkward. If you both like each other, then you'll both naturally pick up on body language anyway. That's why I wouldn't recommend just picking a random dude and going for it. First of all there's possible danger if its a stranger, not to mention STD's and all... I think if you're willing to wait for a relationship with then you might have a better time.
>>5 I'm so sorry. That sounds really bad, it might be a good idea to talk to someone if you haven't...