Carter's ton was a milestone effort for the young batsman of immense potential and came on the back of a six-day trial at Lincoln, near Christchurch, where he re-inked his credentials with three solid knocks in four games.
Carter's Cadets teammate Sean Davey, a seamer who can also hold a bat further down the order, was also picked in the New Zealand team for the Townsville tournament in April, where they will clash with India (April 5), England (April 7) and Australia (April 9) ahead of the playoffs.
At stake is the big prize, with all the players under the microscope for the New Zealand team heading to the ICC under-19 World Cup in July and August in Queensland.
Carter said the heat was on last week as a 26-strong under-19 squad picked from last year's domestic under-18 tournament was whittled down to 15. He scored 60 in the opening Twenty20 trial game and backed it up with innings of 42, 8 and 60 in the three one-day hitouts.
Davey, who has spent the past two months recovering from a side strain, was even more nervous and was eased through the trial, producing a best performance of 1-18.
"I'm only just getting back into it after a frustrating last couple of months and I was a bit worried how the body would hold up because I hadn't had a lot of bowling," Davey said.
Carter was also under pressure to produce but the big goal now is to get runs in the quad tournament and push on for the ICC World Cup.
He has been in sublime form for Bay of Plenty, hitting a string of fifties, but it was a relief on Saturday to get past the century mark for the first time as he and Peter Drysdale (46) put on their third consecutive 100-run opening wicket stand.
"The [107-ball] century rushed up on me a bit," Carter said. "Initially we were told to go out and play it as we saw it but then the call came to pick up the rate a bit so we could have a bowl at them [late on Saturday]. It all became a bit of blur from there."
Carter and Davey have both paid tribute to the late John Howell and his son, former Black Caps batsman Llorne, for their input over the years at the Howell Cricket Academy in Te Puna.
Carter is passing on his knowledge, coaching part-time at Bethlehem College, while Davey has shelved plans to head to university, this year at least, to stick around and try to make the World Cup side.
Bay of Plenty coach James Pamment, who is also assistant coach of the national under-19 side, said to get two Bay of Plenty players, and four from Northern Districts, in the New Zealand side was a fantastic achievement.
"Both these boys have worked hard this last year and hopefully it's a stepping stone to them getting in the World Cup squad itself, then maybe playing first class cricket and pushing on to the Black Caps," Pamment said.
"Sean coming back from injury has done well to put himself in the position to bowl, although he really sowed the seed by impressing last year [at Lincoln].
"Joe went into the trial needing runs and got them. I've been talking to him about scoring runs, particularly hundreds that come naturally [so] it was great to see him get across the threshold at this [Fergus Hickey] level this weekend."
Cater's century was matched, possibly even overshadowed, by the bowling performance of Bay of Plenty skipper Jono Boult, with the offspinner taking 10 wickets for the match - 4-37 on Saturday and 6-32 yesterday.
Fergus Hickey Rosebowl scores: Poverty Bay 117 (Danny Gibbs 39, Richard Genge 22no; Tony Goodin 2-20, Jono Boult 4-37; Brett Hampton 1-18, Amandeep Singh 1-25; Scott Steward 1-10) and 139 (Gibbs 23, Sam Tallott 29, Mattie Thomas 24, Josh Bates 21; Goodin 2-14, Hampton 2-26, Boult 6-32) lost outright to Bay of Plenty 223-5 (Peter Drysdale 46, Joe Carter 104, Jono Boult 42, Brett Hampton 17; Tom Clout 3-47) and 34-1 (Drysdale 11no).