The answer is NO. ADHD should NEVER EVER and let me say again EVER be diagnosed before the age of 6 or 7. For many reasons and confunding factors.
ALL children are different. Some are more active than others, attention comes in stages and at 4 months she's wanting to explore and discover her new world.
Better an active child who is interested in the world than one who is cut off and in their own world.
Accept her for who she is, keep an eye on it, be careful not to label her hyperactive as she gets older and if at 6/7 you are still worried then seek help. But she's 4 months so to put it simply, chill out.