NEW YORK — Brandy Cole may have been wearing a blue dress at the NBA draft, but it is more truthful to say she was dressed in pride.

The holder of three degrees, she was not given to hyperbole when she described her feelings on the evening her son Jayson Tatum was selected by the Celtics at No. 3.

“It’s like probably the most joy, after having him, that I’ve ever felt,” Cole said. “You know, how many people can say they actually witnessed their kid’s dream come true? And I witnessed mine when he was 19. That’s just incredible.”

Jayson has called himself “the biggest mama’s boy ever,” and it looks like he made a very good decision.

Cole was a single mom less than a year out of high school when she had Jayson. His dad, Justin Tatum, became more involved in his son’s life after returning from playing basketball overseas when Jayson was in grade school.

Brandy was the earliest architect, leading by example and by dictate.

“I’ve wanted to get him drafted for so long, because it’s what he wanted,” he said. “He’s always wanted to go to the NBA. He told me that ever since he was 3. Had he wanted to be an astronaut, I’d have taken him to space camp. But we made the necessary steps and did the things we needed to do to prepare him for today, and here we are.”

“Here” was Brooklyn last night. And then it’s Waltham today for Jayson’s introductory press conference at the Celtic practice facility. Cole was looking forward to it all, strong in the belief her son landed in the right place.

“I love it,” she said of the Celts’ decision. “It’s just a great opportunity for him. Everyone that I’ve spoken to, whether it’s retired [NBA] veterans, whether it’s young players, everyone just talks about what a great program it is, what a great coach Brad Stevens is, and, you know, the fans are amazing. So, I mean, he’s really blessed. And then it’s a winning franchise.

“A lot of times people talk about how rookies underestimate the transition and how hard it can be from winning your whole life to losing [with a bad team], but that’s not the case here. I think that’s an added benefit for him, as well, so we’re excited.”

When it was mentioned that Duke coach Mike Krzyzewski is a fan of Jayson’s new coach, Cole said, “And my mom loves coach Stevens, too, so we’re very happy.”

Justin Tatum is happy with his son’s place of employment, as well.

“It couldn’t be a better situation for Jayson to come and excel right away and hopefully help Boston with scoring and toughness and just learning under coach Stevens,” said the elder Tatum, wearing a Celtics hat like the one Jayson was given as he walked onto the stage to shake hands with commissioner Adam Silver. “That’s probably one of the best things as a coach myself. I love the way coach Stevens coaches and the way he teaches his players, so I’m just ecstatic.

“When I would watch his teams, you could see the right positions he had his players in and how they fought and never let down, even though they were down to Chicago and Washington. I think it’s the best situation for Jayson. You know, most rookies don’t get a chance to come in and go to a playoff team, especially a No. 1 seed in the East. So it’s great for us.”

Justin has seen Jayson from more than just a father’s view, having to coach against him when he took the job at Christian Brothers College High School in St. Louis. It actually showed character that Jayson didn’t transfer, staying at Chaminade College Prep because he didn’t want to leave his teammates and he was doing well academically.

“I’m his dad. I’m probably just as happy as he is, because that was an accomplishment he always wanted,” said Justin. “A lot of kids want it but never work for it. He worked for it.

“I take a lot of pride, because I’m the one that put the ball in his hands. I’m the one that chewed his butt out and got the grit for the basketball court and got him prepared for what he’s about to go into today. I never took a day off on being tough on him to let him know, hey, you have to be able to do it this way. Then he started to train himself on his own and got the mentality like that.”

Accordingly, Justin Tatum thinks his son has a chance to contribute right away.

“He’s ready from Day 1,” he said. “It’s the mental part. Some guys come in and they’re so excited about being drafted and don’t know really what it takes. He is already there mentally and knows that he has to challenge himself more. It’s going to show.

“The opportunity is there, and I think it’s there for somebody as versatile as he is and what the NBA is transitioning to now. Jayson has the scoring ability to hopefully keep himself on the floor and make sure he plays on both ends.”

There is one way father and son differed. While Jayson was rooting for the Lakers because of his fondness for Kobe Bryant, Justin was a Celtic fan.

“I love Boston, I mean, especially when they picked up the Big Three — the latest Big Three with KG and Paul [Pierce],” he said. “But I’m related to Jo Jo White, too, and he played for them back in the day. We’re related through cousins, so I’ve been a Boston fan for the longest time.”

All parts of the family will now get learn even more about that which is known as Celtic Pride — though Brandy Cole seemed to have the larger concept down pretty well Thursday night.