the big 13m...

OK, so while I polish my no-booze halo (Husband has fallen in a ditch... and now I'm going to verbally stamp on his weakness. You're WEAK Husband. WEAK. - he's been drinking red wine. In my house. Under my nose. And in front of my jealous eyes... Oh, but he's WEAK) I am also trying to buff up my mid-to-late-30's-some-what-unappetising-physique. Buffing up by which I mean, I've set myself a physical challenge. Via my super-fit brother-in-law. Who is a 'big runner'. He ran the London marathon in about 45minutes, and in December he flew out to Las Vegas for some gambling and another marathon which I believe he ran in-between visits to different casino's. With his pockets weighted down with lose change. And on top of all that he raised shit-loads-of-dosh (such a good phrase) for a very close-to-home charity (Saving Faces). So over a drunken Christmas conversation as I shoved my face full of Christmas cake, pringles, brussle-sprouts, olives, smoked salmon, brandy butter, Cadburys Roses, prosecco, toast and marmite, stuffing, pasta, pasta sauces, more prosecco, white wine, red wine, port, coffee, tea, cucumber, humous, butter, kettle chips, peanuts, beer, ginger beer, tangerines, home made fudge, the table, napkins, one Volvo, Father Christmas and a 200-year-old-lime-tree - basically anything in sight went down the cake-hole,  my lovely brother in law propositioned me with a half marathon challenge. Having just eaten Father Christmas and an ancient tree I felt a bit cornered and heartily agreed.
So now on March 20th, you may experience what is more commonly known as an 'earth quake'. Fear not! This will just be me stamping reluctantly and inelegantly around a 13mile (What the..?) track somewhere out in Buckinghamshire.
What I'm currently concerned about is a.) what to wear (does my bum look big in these skin-tight legging things and this strange fluorescent t-shirt which appear to be compulsory clothing for runners?); b.) how the fuck do I get around a 13mile course without dying? And should I collapse at the 1mile mark, how humiliating will that experience REALLY be (for me and then for my family, after-all, they'll be there, at the 1mile flag, with a stretcher...); c.) if I'm feeling really energetic, what's the etiquette for elbowing slow-coaches out the way and pushing them headfirst in the mud, laughing outrageously evil-y, down, ye of little speed?
I ran for about 45minutes this morning, (relief: not in fluorescent - although I was in tight leggingy things which have a certain amount of derrier-revelation... unpleasant for pedestrians who have to witness 'it' as I 'bounce' by like a baboon in trainers...) - and actually, I didn't collapse or wet myself or get heart palpitations or vomit - and when I got home in my blue leggings, I felt, wait for it - yeah, OK!
So. There is hope. There is hope.
Albeit small.
The other etiquette I wondered about running is, so, is it OK to have a pint of Chardonnay at the end of it or do I HAVE to have water?