In most cases you are inserting the tampon into the hymen opening. In some cases you may stretch or tear the opening in inserting or removing a tampon. This is not dangerous and millions of women who have not had sexual relations use tampons. My daughter wants to use tampons, but I'm afraid that it will take away her virginity. I have heard that if you use tampons long enough and if you do the splits and active stuff like that then you can lose your virginity.
Many young girls start using tampons early on because they are swimmers or athletes.
The hymen, which partially covers and protects the opening to the vagina is so fragile that it is stretched or torn during many activities. I see no reason why your daughter couldn't use a tampon if she can read and understand the instructions for insertion and safe use. The decision is yours and hers. The most common one is pregnancy, but it could be caused by stress, or physical illness, etc. The possible signs of pregnancy are missed menses, tender breasts, fatigue, frequent urination, morning sickness, etc.