my granddaughter had sex for the first time about 6 weeks ago. she is 14. her period in september was the last week of the month into the first few days of October. She had sex some time after her period. She then started her period again around the 17 or 18th of October. Is there cause for concern. Can she be pregnant. Will she start on time this month. She started her period when she was 10 and has never really had a regular period. By that i mean she sometimes had a period the first week , the second week, the third week, the fourth week, but here lately they were somewhat regular. Please give me some advice and answer my question.