Your mom is right. Whiten strips can make your teeth sensitive. You may wish to find a product that has a lower dosage, or use them for a shorter time. If you find your teeth are getting sensitive to the strips you may wish to stop treatment for a while. However that being said, it is still something your mom would need to approve of before you go ahead and use any whiten strips. Maybe ask your mom if you can first start off with using a toothpaste product with whiten.