Tampon question......?

I'm 12 almost 13. My mom never talked to me about tampons so I don't wear them. I started my period almost a year ago. The problem is that I have tennis for 6 weeks starting July 5th and its uncomfortable wearing pads while playing. Last year it leaked through my shorts and I never realized until I got home and I felt so embarrassed. It feels awkward talking to my mom about these things and I don't really want to talk to my older sister (She's almost 26. I'm know she still wears pads but I don't know if she wears tampons.) about these things cause she can be judgmental and then she'll tell me mom. What should I do?