Is it normal to start having sinus arrythmia even though i never had it before?

The older you are the higher chance of cardiac arrhythmia to occur. Sinus arrhythmia is not uncommon and relatively benign so you should not worry much although it is not a normal rhythm. Take care.

What sinus arrhythmia are you referring to? What symptoms are you having? How was it discovered? You should see a cardiologist to review this with you to determine if the arrhythmia you are experiencing needs treatment or not. Best of luck to you!