Most girls start their periods between the ages of 12 years and 14 years, but some start earlier or later. When you first start having your period, it may last only a few days. Your first few periods may be very light. You may only see a few spots of reddish brown blood. Anywhere from 2 to 7 days is normal.
https://www.acog.org/Patients/FAQs/Your-First-Period-Especially-for-Teens
A menstrual cycle is counted from the first day of bleeding in one month to the first day of bleeding in the next month. The average menstrual cycle is about 28 days, but cycles that are 21–45 days also are normal. It may take 6 years or more after your period starts for your cycle to get regular.
https://www.acog.org/Patients/FAQs/Your-First-Period-Especially-for-Teens
Anyways you count from the first day of your period until the first day of the next one. you count 28 days from the first day of your period, so if your period is 7 days then it would be 21 days after the last day of your period. Well since day 1 is when you start your period 28 would be your pick......however, some cycles can last up to 32 days or more, so there's really no correct answer here. 28 days.
https://answers.yahoo.com/question/index?qid=20080114055544AAzcllq
Menstrual Period, Late or Missed. A menstrual cycle is the time from the day a menstrual period starts to the time the next period starts. The average menstrual cycle is 28 days long. However, a normal cycle can be shorter or longer than this. It may be anywhere from 21 to 35 days long. Most periods last 3 to 5 days, but anywhere from 2 to 7 days is normal. Menstrual cycles may happen around the same date every month or they may be irregular. A menstrual period is considered late if it hasn’t started 5 or more days after the day you expected it to start.
http://www.summitmedicalgroup.com/library/pediatric_health/hhg_period_late_or_missed/
Each body is different so the exact amount of time I cannot tell you. I'm on Femcon FE and it normall takes me about 2 days to start bleeding after the last pill is taken. The… pill is in your system for apprx 24 hours so any time after that you can start bleeding. This is because your body does not actually have a period.
http://www.answers.com/Q/How_long_until_you_get_your_next_period
Do you count 28 days from the day of your last period, or 21 days. Or maybe its count 21 days from the first day of your last period. Or maybe its….oh, please help!
https://answers.yahoo.com/question/index?qid=20080114055544AAzcllq
It’s normal to get your period as early as 9 years old or as late as 15 years old. This is a big time range and it’s hard to be one of the first or one of the last. Girls who are active in sports or are very thin may not get their period until a later age.
http://youngwomenshealth.org/2010/04/21/menstrual-periods/
You should get your period about once every month. A typical menstrual cycle is about 28 days. This means that there should be about 28 days from the first day of your period to the first day of your next period. 28 days is an average number, but anywhere between 21 and 35 days is normal. In the first year you should have at least 4 periods, the second year at least 6 periods, and for the 3-5th year, at least 8 periods. Adults should have at least 9 periods a year. Your period will usually last between 3 and 7 days.
http://youngwomenshealth.org/2010/04/21/menstrual-periods/
How long after a miscarriage until you get your period?   Answer     It took me 8 weeks to get my period after I naturally miscarried at 12 weeks, though the abdominal sac was only dated 6 weeks 2 days.     So i…n all I miscarried in May and got my period in July --exactly 8 weeks 2 days.
http://www.answers.com/Q/How_long_until_you_get_your_next_period
Amenorrhea means not having a period. It is normal for some girls not to start their periods until age 16 years. However, your doctor may want to see you if you have not started by age 15 years. You also should see your doctor if you have started your period but it then stops for more than 3 months.
https://www.acog.org/Patients/FAQs/Your-First-Period-Especially-for-Teens
how many days until my next period is to come
It is about 28 days until the next period is to come. It takes about 28 days to your next period. It takes about 28 days until your next period to come. Your next period day will come in about 28 days. There are about 28 days until your next period is to come. Your next period will come after 28 days from the first day of your period. Your next period is coming until 28 days from the first day of period to the first day of your next period.