Should I worry?!

Only if you've done it...but I wouldn't cuz it happened to me once as well O.o

Very true.

I'm still a virgin so it'll come.

You should be fine then :)

Zanesaaomgfan - if you're still a virgin then i wouldn't worry to much about being pregnant :) that's one relief, but girls can be late on their period due to many other things.
Their diet for one - if you're not eating enough iron (such as green vegetables and red meat) then it could mean your anaemic (however this would have to take years to develop)
It could also be your weight. If you're underweight for your age/height it could be due to that.
Also if you're still young it could be due to you just growing up :) Periods tend to be a bit dodgy in teenage years, i remember i once had one for three weeks, then went two months without one before it finally settled into a routine.
But it could also be down to stress. If you're highly stressed or upset about something that could cause your body to shut down certain things to completely concentrate on what it is that's bothering you. If that's the case, get a cup of tea/coffee (herbal is best) sit down somewhere quiet and just relax. Just make your mind totally free of everything and anything and just forget about everything. Also massages, aromatherapy, music therapy or crystal therapy could help too. if you need any instructions on how to do any of that just send me a message (but i'm not qualified i just like to study and do them in my spare time) :)

^ Also true. :)