Hi
Firsty, I'd suggest having a browse around an excellent, evidence-based breastfeeding website called kellymom.com, which is a wealth of great info on all things boob-related.
The thing is, there really is a massive range of behaviours that is perfectly normal. There are all sorts of things that could account for the feeding pattern your DD is choosing: you could have fast let-down/fast flow, and actually she's getting a great meal in those 5-10-20 minutes she's on each breast. When she's choosing a very short feed, she might just be thirsty, deliberately avoiding the richer milk.
The thing is to look at the whole picture: Is she content, alert in between feeds? Does she look healthy? Does she appear to be gaining weight within a normal range (with the usual proviso that weight is also just part of the picture)? Is she producing plenty of wet and dirty nappies that looks about right? Is her latch comfortable for you? Does your breast feel drained after a feed or still quite full?
I have come across plenty of babies who are very quick feeders, and plenty who really blooming take their time.
It maybe that short feeds are just normal for her. But again, look at everything related to feeding before you worry, not just the time.
One thing's occured to me though: do you always offer the same breast first? Some babes do seem to find one breast preferable to the other, and fuss more at one than the other. How long does she generally (if there is a generally) stay on the second breast?