The time is soon coming where Jesus would die on a cross on behalf of humanity. But that doesn't mean that Jesus did not have any internal struggles. Jesus proclaimed that "[His] soul is troubled" and thought about asking Father to save Him from the hour (12:27). Having difficult feelings in difficult scenarios is a normal thing, and it is okay to simply have them.
But even with those feelings, Jesus proclaimed that "for this purpose I came to this hour" (12:27) and asked the Father to glorify the name of the Father (12:28). Rather than getting overwhelmed by emotions, Jesus kept His feelings in check, prevented the feelings from distracting Jesus, and focused on the Father. The attitude of persevering in the midst of struggles is difficult, but Jesus mastered the attitude for our behalf.
Eventually, a big voice from heaven boomed out and proclaimed that Jesus has been glorified and would be glorified (12:28). The prior glorification can refer to an instance where Jesus was glorified beforehand (probably the scene where Jesus entered on a donkey). However, the latter glorification would happen during the scene of the cross/resurrection where Jesus overpowers death.