Tanks so much am not really sure about lmp could of being 18th nov that Wat i told my doc an she give me a due date 25 August based on lmp so if my lmp was on 18th do u tik I conceived before the 3rd of August
LMP is not a very accurate way to determine when you conceived. You sometimes ovulate out of sequence, and as you are saying, some women cannot remember their LMP dates accurately. An ultrasound scan between week 6 and 8 is by far the most accurate.
Knowing that that date came from your LMP, it is possible that sex on Dec 3 could have gotten you pregnant.
95% of all women ovulate between 12 and 16 days before their next cycle. The 14 is just a handy average. LMP is however not the most accurate way to determine. You are trying to get an definite answer where none exists. Are you just curious or did you have sex with multiple men in that last week of November and first week in December?