Yes it's okay for 13 year old to use tampons or whatever else they want during soccer or any other activity they want to do on their period. Tampons are not recommended to teens due to increased risks of TSS so you need to make sure you understand the risks and how to use tampons correctly to reduce risks. You may want to consider using safer more reliable options like menstrual cups.
Yes, you can wear a tampon while taking doxycycline, no matter the reason you're taking it. Even if you are being treated for chlamydia, wearing a tampon will not affect the treatment.
A tampon
Yes you can, but you will want to wear a tampon.
Yes girls can play soccer with their period, although personally I would wear a tampon not a pad. Good luck!!
A tampon obviously
No, soccer players are not allowed to wear hats during matches.
Soccer players typically wear a jersey on their chest during a match.
No, soccer players are not required to wear a sports bra during matches.
Soccer players typically wear sports bras during matches for support and comfort.
Toatally
Yes, you can wear a tampon after urinating. Everyone urinates at some point, and urine comes out of your urethra not your vagina, so I'm not sure why you would think that you'd not be abel to wear a tampon after urinating.
Some soccer players wear sports bras during matches for added support and comfort while playing.