Welcome to HCM,
You haven't mentioned composition of Norzette, thus it is not clear that whether it is an oral contraceptive or emergency contraceptive pill
As it seems to be a hormonal
pill, it have side effects.
Hormonal pills on long use, can cause infertility
, thus shouldn't be used regularly.
At the age of 17, you are fertile. Therefore you should avoid unprotected sex.
As condom protects you from STD
also, always insist for use of condom.
Emergency contraceptive pill should be taken in emergency like slip/break of condom only.
Thanks for trusting Healthcaremagic and posting your query.
Hope you found my response to your query informative and helpful.
With good wishes,
Dr.Chandra Shekhar Sharma