Bambi,very hard to say,what do you normally train at ie pace etc..how did you feel after the 10k...you could start to fast and blow up half way round..if this is all new to you ,my advice would be to start at 10k pace and feel your way into the race...ie 1-2 miles at a good speed and if you feel comfortable ...kick in and have a go.
Some of my best races though have been when i have thrown caution to the wind and then just gone for it..some times you suffer,but thats running.