"Some doubted." I don't think it is so much they doubted what they saw. They doubted themselves, that the Risen Jesus should come to them. They had so many questions about him and about themselves. Why did he come to me? I have not completely worked out who he is. Can I do what he asks with my weaknesses and questions?
But Jesus chose these eleven. God is satisfied with unfinished people. Perfection is not needed to be a friend of Christ and to be called to do something. Stop waiting or holding back until you get it all figured out. Stop focusing on your faults. I would still be thinking about becoming a priest if I thought I had to be more perfect. I bet those doubters, those imperfect disciples went off the mountain and did some pretty good things. Beware rather of people who think that they have it, and themselves, all together.