If you mean on the first packet of 21 pills, it depends, but it will start some time during the week with no pills and should settle on a certain day which is very useful to know exactly when you will get it.
1-2 years after your first one.
One or two days....three tops.
You can't predict how long your first period will last because you need to keep track of how long your first few lasts in order to predict how long one will last. For most people it lasts about a week.
You don't, take one now.
it depends from one girl to another. it may take place 10 days to 1 day before your period
There is a four year period between Commonwealth Games.
If you take your first pill on the first day of your period, you're covered from day one. If you start mid-cycle, your entire first pack is ineffective, and you can't count on it being effective until you start your second pack (and that's assuming you've taken all the pills in the first pack correctly).
prolonged use of medicine is where you take one specific medication for a long period of time.
You are born with all the eggs you will ever have. One of them a month is released by your ovraies.
The rotation period of Venus is equal to about 243.02 Earth days.
I'm not really sure because I only have one period a month but I would take one now just to ease your mind and if it's negative take another one in a week or two if you still haven't had a period.
Ceres sidereal rotation period is about 0.3781 days.