Don't worry if you get it in a swimming pool - I'm sure you'll be fine & if your nurse doesn't have pads/tampons you could take some in yourself or ask a female teacher. And when you do get it, it's not like a river - I only got spots at first when I started, and then it started to get heavier.
You could probably even get send home. When I was at highschool once I kinda forgot my period was due and we had practise exams and lucky me got the period half way through the exam. I knew I'd come on because I could feel it and I panicked - But I had to wait till the exam had finished and then went and told the nurse. I explained to her what happened and she got my mum to pick me up, so I got most of the day off school
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I really wanted my period - and I didn't get it till I was 14..I started to think something was wrong but I got it eventually. I had a smear test done a couple of months ago and everything is fine anyway
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