God knows how we work.
Before you say "thanks Captain Obvious," there's a reason to bring it up. God knows that the 1st time we see something, we won't really get it. Which is why the Bible is full of foreshadowing and previews.
With something as big as the Resurrection, there's a lot of it. The idea of resurrection shows up in both the Old and New Testaments. There's direct foreshadowing, like with Lazarus.
And there's even a preview of the Resurrected Jesus - the Transfiguration.
Which is why there's nothing in Sunday's Gospel about doubting Peter (or doubting James or John). When they see the Resurrected Jesus, they have no doubts. Because they've seen this before.
More on this tomorrow. Readings for Divine Mercy Sunday