Do tampons hurt when you insert them ? Girls Only !?

Ok so I'm only twelve and I've already had my period a few times before but I've only used pads.The problem is is that I swim a lot and my family and I love going to the beach and waterparks and all that. What ruins the whole thing is the period. My mom vowed never to let me use tampons till I was way older but changed her mind because of how I much I loved going into swimming etc. She now wants me to use tampons. I'm really scared that it will hurt after all you have to insert it in well you know and that kinda creeps me out. Help ?