Is faith rational?
Absolutely. A father is teaching his son to ride a bike. The son is afraid of falling, but the father says "I will have my hand on you the whole time. I will not let you fall." The son has no way to prove this, but he knows his father loves him.
So the son steps out in faith. He trusts his father to be true to his word and rides the bike. The father does not let him fall. What's so irrational?
I can say I don't think it's rational. Not really at all. But it's necessary.