My question is: I'm 42 yr old male who has A-Fib and been given Metoprolol Tartrate 25MG. Should I take this medication even if my blood pressure is normal at 124/78 with a pulse of 78 bpm?

I'm afraid it will even lower my blood pressure than what it is.

If your blood pressure was normal when you saw your doctor, why did he give you blood pressure medication? I think you should be asking your doctor this question.