Carmel,
As you may remember from your first race (& others) it's the turning up that's the hard part! Once you get going it won't matter hpw long it takes. What might be a concern is to try going too fast. If you haven't run the distance before then you've got a few weeks to put in longer 'long runs' than you're used to. Increase the distance a little & slow the pace a little. Perhaps try 7 miles @ 10'30", & if it feels OK the next week try the same pace for 8 miles. If it feels like it's too much, go for 11 minute miles. Without being macho I'd say have a go. We don't want to get injured, but it's by pushing that we achieve.
Now that you've posted the query, do let us know what you do!
Good Luck Carmel.