I know from my own experience that I didn't feel I was ready when I first played for the All Blacks. It got to halftime and I thought, 'wow, that was fast'. Then it was all over before I knew it. I felt like I could have played again. The adrenaline pump is that good.
The other thing to remember is that, if one of these youngsters is given a go against England, they are going to have some pretty good, experienced players around them. The props are likely to be Owen Franks and Tony Woodcock with Sam Whitelock and Brodie Retallick at lock and Liam Messam, Richie McCaw and Jerome Kaino (if Kieran Read doesn't come right) in the loose trio. That's not bad and all the new boy will have to do is his job.
I'm not sure there is much between the contenders.
Coltman is a bit hot and cold for me. Marshall has got around the track well but needs help with his throwing. I don't think that's such a big problem — even Anton Oliver still needed help with his throwing in the last few years of his career.
Harris has played well and might be the one to go with first up. Keven Mealamu is always there if needed and, for the June series at least, so too is Corey Flynn.