I normally start my period around the 17th 18th and it normally last 5 to 6 days. This month it started on the 13th and went only 3 days. Not sure if this is normal or should I take a test or what...

If you are concerned see your OB/Gyn

The first symptom of pregnancy is a missed period. Since you did get your period, most likely you are not pregnant. There are many reasons for variations in manstruation, pregnancy is not one.