Based on your prayer request I recently read in the Prayer Room, I'm going to assume that this is for school. I'm also going to assume that you have practiced this presentation and have timed yourself doing it at 8 minutes. I would definitely add more to it, since people usually speed up when they're actually doing the presentation, usually to get it over with (learned from Public Speaking, Comm. 100). If it's 8 minutes now, it could end up being 6 minutes when you actually do it, which would probably hurt your grade. What I would do (and have done) is get at least two minutes
above the time limit while practicing. That way, you have two minutes to play with during the actual presentation and if you speed up, then you should fall right around the 10-minute limit.
What really helps is if the teacher said at least 10 minutes; it never hurts to go a
little over time if it ensures that you'll be at the minimum.
Oh, and I'll surely pray.