A mirror is often helpful when you’re trying to insert a tampon for the first time, so that you can see exactly where your vaginal opening is. You can also try using a small amount of vaginal lubricant (K-Y Jelly) on the end of the tampon to help it glide in.
If you’re not able to insert a tampon after several tries, make an appointment with your health care provider. One reason for this is that you may have been born with a very small opening in your hymen, which prevents you from inserting tampons. This is true in only about 2% of teens, but it could be a problem.