Think of it this way - would you have bought the house under any other normal circumstances?
If not, it's probably not for you.
One of the big adages of property is that it's easier to sell a bad property in a good area than a good property in a bad area.
And as Dru points out, we haven't even seen the bottom of the property market yet.
IMO, wait till it does bottom out, then ask yourself what house you would like to buy, in what area, and how much you can afford.
I think that's a far more important set of questions to ask when buying your first property, than "can I help a friend out by loading myself with the biggest debt I'll ever carry".
That's just my 2c though.