I had two boys that had the same problem. They are now 12 and 6 and yes, it is a problem. The first thing we realized was that if either parent had dental problems, it's almost a sure thing your kids will. My husband had extensive dental problems complete with massive head gear. His mouth was very small, high palate and large teeth. He wore braces for 3 years. These days, they do start early - very early, in addressing crooked teeth and that's a good thing. My 12 year old will need braces, but we cannot afford them right now. My 6 year old had massive cavities even though we brushed very well and took him every 6 months to the dentist starting at age 3. He had to have one tooth pulled, two baby root canals and 4 caps! We felt awful, but there was little we could do. It was recommended we start orthodontal work before he turns 7. He has severely crowded teeth yet to come through and many won't make it if others are not pulled to make room. It's a long process of lots of x-rays and targeted decisions about which teeth he'll need and which ones he will not.
The next time you go to the dentist, mention your daughter's teeth and let him advise you, but when it is time to get her seen, only go to a pediatric dentist. That is where we made our first mistake with our youngest and why I believe they missed his cavities. Pediatric dentists have are like specialists and I have a new respect for them.
Good luck!