Period-delay tablets are commonly used and generally safe for occasional use, but since you've never taken one before, a doctor needs to check your health profile first, especially given your weight of 46kg, before prescribing the right option for you.
Next Steps
With your period expected around day 27 to 28, please see a gynaecologist within the next day or two so there's enough time to start the tablet before your cycle begins, since timing matters for it to work.
Health Tips
Avoid starting any period-delay tablet on your own without a prescription, since the wrong timing or choice can cause breakthrough bleeding.