all babies are born with flat feet, and all children have them until they are around 4-5 years old.
there is no arch as such in the foot until then.
thats not to say youre child may not have a problem. if the rolling in or "pronation" is really marked it can be a sign of a condition called ligamentous laxity - used to be called double jointed. being flat footed can also be hereditary, and usually does not cause problems - it used to be thought that it would cause hip and knee pain, but now it is know that the other joints in the body will "compensate" for the flat feet and to try and correct the condition will actually cause pain in other joints - there are other neurological conditions which will cause flat feet, and they are usually accompanied by what is called a slapping gait, or a lack of control over placing the feet on the floor.
do other joints in her body seem abnormally flexible?
toe walking (technical term is ankle equinus) is another problem - and if she does that a lot it should definately be checked out - habitual toe walking can shorten the calf muscles and lead to long term problems, and can be an indicator of neurological problems.
so when you say tip toes a lot - do you mean all the time, or just sometimes.
if your daughter has any of these signs you should take her to a podiatrist and have her evualuated.
hope this helps (podiatrist for 12 years)