My new, awesome ped will not even give you %. He just doesn't want parents stressing about %iles when they just aren't that meaningful. You have to remember that baby's genetic programming comes out in the first year. If she is going to be a big or small kid is influenced by genetics.
My ds1 had been at most 90% in the first few months but buy 9 months he was 25%. The ped never batted an eyelash. He is almost 6yo and that is just his curve. It just took a bit to find it.
Finally, have you ever really looked at the growth charts? Those lines are so small and hard to read that it is easy to mismeasure.
If she is growing (length counts too!) and seems happy and healthy then I think you are right on track. Bf on demand and I think you'll do great.
Beth