I need info

Kennia

So im 14 and just started my period when i was 10 is it normal for my period to be a few days late last month i was supposed to get in on the 19 but it came on the 23 this month i was supposed to get it yesterday but still havent gotten it is there a reason as to why? I only know the basics about periods but im totally clueless as to why im late should i worry about it?