Well done on getting this far... this is when you will feel like you need to be online all the time!
For fear of repeating (Emmy, and Flat footed )-You said you have 4 kids- how old are they, and how do you anticipate fitting in the training (esp over the winter)? Is your other half very supportive and prepared to take on childcare, or are you planning some graveyard shift sessions Ie start of the day/end of the day? (I speak from experience of the latter, and I've only got 2 kids)
If you don't get through, are you going to run a marathon next year? If so, which one and why....
Congratulations! You said youu have done some triathlons- what have you done, and what made you want to come back to running? how will you manage the time and commitment of training for a marathon over the winter?.