Pregnant or not??

Megan💖 • 1st baby due on Christmas Day 2015 ❤️🎄👶expecting a baby girl 💕
So my period came last week the 14/3/15 Saturday and I finished Wednesday 17/3/15  had sex Thursday, is there a good chance I could be pregnant, really want to do a test but I know it's to early and would just get a BFN 
Busy dust to you all ✨