What Does My Ultrasound Scan Report Indicate?

Question: Hey Doctor I have an extended question for you regarding a Conception situation. I had sex with a girl on March 18,2016 and April 5 2016 which was the day before the start of her LMP. She had an ultrasound done on XXXXXXX 2 2016 which stated she was 8 weeks and 1 day pregnant. She also mentioned that she had been having sex with another guy around April 18-27 of 2016,but said she had protected sex with him and they only had sex ONE TIME!! however I don't know If that's true. Can you explain to me what are the chances she was conceived . I am unsure if she got pregnant by me or the other guy. I use the pull out method but I don't know if that was enough . Also she is saying her doctor said she got pregnant the week of her LMP is that true? From my understanding , the fetal age is usually 2 weeks less than her gestational age. If this is true how can this possibly be my child if we only had sex the day before her LMP which was April 5,2016. She also said the doctor gave her the expected due date of January 11,2017(40 weeks) . Overall based on all the information given what could have possibly happen wrong in the ultrasound scan and or the information given for her to believe the child is mines and not someone else. I am basically asking what are the chances this could be my child based on the facts of the information given in the scan and what's is given in the discussion. Can the fetal age and gestational age be the same or that close in the week? Have you heard of any special cases where this could be possible? I need to ensure that I am not the father of the child? Also I was researching about ovulating periods and found out that most ovulation can occur 11-21 after the first day of the menstrual cycle or 12-16 days before the next expected period. She has had the baby today and that is 6 days earlier than her expected due date from her First Ultrasound scan. How could that be possible if her EDD was XXXXXXX 11,2017. Does this mean the baby is mines, as stated before we havent had sex since April 4,2016.

Please see the scan provided in the upload section of the follow-up question right here. I see two dates The April 5th 2016 date is there and the XXXXXXX 2,2016 date is the actual date she had the ultrasound scan performed. And it says the age is 8 weeks and 1 day pregnant from April 5th. If we had sex the day before which is April 4th how many weeks would thw scan read based on that..
Would the age still be the same ??