Well done, that's a great first time, especially in the conditions. It looks like your long runs really paid off.
The first mile in a big marathon is always annoying and you have to write off the 'lost' 45 secs or so, rather than try and make it up over the next 2 or 3.
Always a big decision whether to travel on the day or stay somewhere near the start. Familiar food and familiar bed versus a couple of hours driving, but I found I don't sleep well in a hotel and get up anyway at 4am or so.
Congratulations.