When i was about 11 years old i was told by my family doctor i had an irregular heart beat. will my heart rhythm always be irregular?

Not necessarily: You may simply check your own pulse - at the wrist or at the neck or groin - to see if you can pick up any irregularity; ultimately one would have to have their heart trace recorded (EKG, electrocardiogram). It is done either at once or during a period of time (24 hrs), if indicated. Check with your doctor again, if there is any concern