How is she becoming sore in the real question here? Are you pumping too hard, going in too deep or does she not stay wet enough? If the vagina beings to dry and not secrete vaginal fluids to keep it wet and you may need to use a lubricant like Astroglide or KY. A little more info is needed to make an accurate decision, there could be lots of different factors involved in this.
WOW! I am glad to be above the average. 30 minutes of actual intercourse if I really try? I can make it take hours if I wanted. She doesn't like it past 10 minutes or so. We play alot and she really enjoys it but she gets sore after about 10-15 minutes? So how long should normal intercourse last?
Well pat yourself on the back ;) Kidding.
Average size is between 5-6 inches erect.
Lasting too long... How long is too long? Foreplay will certainly cure that. Tell her to play a little longer ;)