What would happen if I got my peroid and i go swimming for a long time?

Okay so I am 11 turning 12 in July and I got my period on may 2010 then April 2010 then in june we I went to hurriacane harbor and that week wen I went to hurricane harbor I was expecting my period and they say it's not good to go swimming wen ur on ur period but I did I it's gunna be July 2011 and I still haven't gotten my period so like I haven't gotten my period in over a year CAN SOME ONE PLEASE HELP ME!!!