Looking for some advice here. My 15 year old son wants a house party (which I'm happy for him to have) but he's asked for 40 people. I have a 4 bed semi with an open plan kitchen/diner/sitting area and they can have access to the garden but I can't help but think this will be too many. I know there will be alcohol (I won't be providing it but I wont stop them bringing their own) I will be in the house the whole time and will be very strict at who comes through the door. I'm a bit scared that my house will be trashed - can anyone offer an advice.