28 days since last period could you be pregnant?

I really think the answer is yes you can because you have a gestation period of a certain amount of days that your not ever supposed to hav un protected sex if your not using Birth Control it som any days before your menstrual period and about a week after it you are still very fertile during these periods that why a lot of ppl that have to wait until the ovulation period and that is thattimein between your cycle if your every 21 days or every 28 days that you can and will concieve, if your able to bare children. I hope that this answered your qquestion but, theres always a better answer? Right, but anyway good luck, either way if your in that situation or know of someone who is!