Asking for tampons...

So I normally get my peroid at the end so sometime this week... my family and I are going to the beach this weekend and im scared i won't get to swim because of my peroid... I tried to get tampons acouple months ago but my mom said no and that you can get sick form it (which I know I did my research) but she wouldn't let me get a word in.. She says that TSS is a allergic reaction to them (which it isn't... righ?) but I want to bring it up again and try to convince her but I don't know what to say... any advice? Also what's your favorite kind? I'm 15 and have been having my peroid (regular light to heavy flow) since I turned 13.