H bears and Kattefjaes - thank you. It was partly the lack of miles in my legs that worried me, and unfortunately I only managed one and a bit marathons rather than the planned two! But, you know, nothing terrible happened, and the nerves are past now... until next time
I'm currently feeling sick with nerves at the thought of the marathon I'm running tomorrow (and the one on Sunday too, for that matter), so this resonates with me.
With practice, it gets better... or at least you learn that it's not going to kill you. I get nervous before a lot of things (giving lectures, like Zouse, is a favourite) so get plenty of practice!
The only thought I've found that helps me, is that I've been very nervous before some of the coolest experiences I've had (marathons, trekking trips, mountains, whatever), and remembering that helps me think of the nervousness, as anticipation. If that makes any sense.