I wouldn't worry about it unless she hit something to make it loose. My daughter had lost 4 teeth by the time she was 5 years old and all of her adult teeth came in just fine! I spoke with the dentist and he said that the earlier they get teeth, the earlier the baby teeth will fall out. My daugther started teething at 4 months and by 8 months had 8 teeth, so don't worry!
Every person is different, so let her grow at her own pace. Have a great day!