We have no way of knowing if u are or are not you just have to do what all of us did and that's wait until your period is late... get a pregnancy test... read instructions on box.... follow said instructions.... use the first pee of the day... wait for results.... if its negative... wait 3 days and repeat process.... good luck...
Since you don't know when you ovulate - some women ovulate early, and some later. And the fact that sperm can live inside you for around 5 days or more in healthy cases then generally speaking there is no safe time to have sex. The most likely time to fall pregnant is by having sex mid cycle and not on the 6th day of your cycle, but it could still happen so you never know. I would say chances aren't high, but still there which is why you should use condoms at all times if not trying to conceive.
U have to ovulate, which is normally around 12 to 14 days from the starting day of your period