Tampons

Ok so I got up this morning really happy because my period hadn't started yet and I was going to go have fun and hang out at the pool but in the middle of the day while trying to help my mom pick a favorite of wig at store I start getting this feeling so I go to a restaurant across the street to use the restroom and GUESS WHAT!!!! IVE DONE START MY GOD FORSAKEN PERIOD... So I asked if I could still go to the pool and my mom said no but then her friend says "I gots you a sOLUtIon". Tampons. I'm 14 years old and I've never used a tampon. But. I. Want. To. Get. In. The. Pool. Should i try a tampon and enjoy my day and is it safe to get in the pool with a tampon? Or should I forget about it?