Having stabbing pain in vagina what could it be?

Not enough info: If you really mean 'stabbing", it might make sense to see your doctor. Extreme pain is never good to ignore. If it's not so bad, you can just watch and do that if it gets worse or lasts too long. While there, try to get info on how to know and care for this part of your body - inside and out - through the cycle too. Knowledge is good! Take care/be well!