Yes, it is normal to have a period every 18-21 days but it is a short cycle. A typical menstrual cycle is 28 days and everyone is different, but a shorter cycle may imply possible fertility issues in the future so if your cycles continue to be this length and you want to TTC talk to your doctor.
Ya somtimes that happens but to girls around the age of 15 to 18 if your not that age you should see a someone about it.
It could still be your period. When I was 18 I got my normal period,then started spotting a few days after.(that had never happened before) Turns out,I was pregnant.So,it's either still your period,or you're pregnant.
Mosquitos have a gestation period of 18-35 days long.
No this is not normal. Go to your maternity hospital or accident and emergency department.
The 'normal' cycle is 28 days from day 1 to day 1 of your period - give or take a day or two. If you're having periods much sooner than that - I suggest having a chat with your doctor, just to have a check up and put your mind at rest.
no
Anywhere from about 16-18 days.
Most women ovulate 14 days BEFORE a period is due. If you mean you spotted 18 days after the END of your period this would be day 23 - 25 so it may be implantation bleeding, if 18 days after the START of your period it could be anything.
18-22 days 18-22 days
The gestational period of a mouse (house or pet) is 18 to 22 days.
18 days17 days
Yes, that's normal - the average age of menarche (first period) is 13 years old, but anything between 8 years old and 18 years old is considered normal. In fact more girls are reaching menarche from earlier ages these days due to environmental factors.