I just happen to know a wee gal from Ireland who didn't think she could run 10 miles. Then she turned around and did just that. Don't get me wrong a half marathon is not for the feint of heart, but you CAN do it. The trick is to follow a good training program. As far as pace goes, I know a couple of really fast runners who fold like a deck of cards if you ask them to run more than 5 k! No worries!