No.
Not if she had been having (fairly) regular menses before. See a health care professional about your concerns.
Yes, it's normal. You might not be regular for maybe months or years. I got my period when I turned 13 and I am now 19 and still dont have a regular period.
Most periods last around 3 to 7 days. If yours is 13, that is not dramatically different. Every girl is different. Therefore, every period is different. A period of 13 days would be normal if the same person always have it for 13 days. If the person usually has a 4 day period, for example, then has a 13 day period, that isn't normal. Remember, if this is one of the first few periods, it is supposed to be irregular Once a regular period starts, then it should stay regular.
I was the same way. I dont know if it is normal or not but I am 19 now and my period is regular.
It is fairly normal, as teenagers periods are not always regular because their hormones have not fully regulated yet. However, if she has had sex, she should take a pregnancy test. If she hasn't had sex, it might be worth going to see a doctor to check everything is OK, which it probably is. It is probably caused by stress, anxiety, tiredness, travelling, illness or not eating properly.
No, that is normal.
i am 44 years old and always had a regular 28 day cycle, it as now for the past 3 months changed to 26 days, is this normal? it is not heavy or painful
Yes, this is completely normal - it takes time for your body to reach a point where it will ovulate on a regular basis in order for you to have a regular menstrual cycle.
Yes, this is completely normal. Irregular periods are normal within your teens as it takes time for your body to get into a regular pattern of ovulation, and thus into a regular pattern of menstruation.
While it is not normal, it is a side effect of the MAP. Not all women experience this side effect and even if you do this time is not an indication that you will or will not the next time. It is not a normal period and you will have your regular period when it is due or within a day or two of that time.
Yes
Yes, it is very normal, you might even end up with a regular period after stopping the pill.