Had sex 1 day before my period and now its 3days later and period still haven't come down can I be pergnant

Any time you have sex, you can become pregnant. It may just be a late period.

Ok I was just wondering because I don't get late period and I had sex 3days before my period last month and it came on the next day but this month I had sex 1day before and its been 3days now and still no sign of it

You will have to wait. If another week passes, take a pregnancy test.

You are having regular sex, if not pregnant this time, give it a few times and you will be.