Is atrial fibrillation dangerous to have?

It can be: It can lead to stroke unless you take anticoagulants.

It depends: Appropriate management can lower the risk. Specifically, the heart rate needs to be controlled and stroke risk needs to be addressed. Specific guidance should be available from your physician.

It can be : Increased stroke risk is the major consideration here. Talk to your cardiologist about what yours is & whether you should be on blood thinners or just Aspirin (for lower risk patients).