Do you ovulate 8 days after your period finishes every month and is it normal to have light blood when i wiped but this has only happend once ?

14 days before: An easy way to remember ovulation is that it occurs 14 days before your next cycle. If you know how many days between periods then you can calculate an approximate ovulation date. Since you are 17 hopefully you are not trying to get pregnant. Relying on cycle timing for birth control is very risky. Start birth control and avoid these scares.

Ovulation: It depends on your length of cycle. Typically women ovulate mid cycle. Normal cycle is 28 days so one would expect to ovulate around day 14. If you have a 6 day menses, then yes, you could ovulate 8 days after the end of your period. having some light spotting or pains around that time can be normal.