Be disappointed about not getting Zion Williamson if you want, Knicks fans. But you should also be excited about RJ Barrett.

There seems to be a dejected feeling among some fans about Barrett, that not only is he far inferior to Williamson but that he’s not much of a prospect, period, and that the fan base is only reluctantly accepting him. I’m just not sure what people aren’t seeing here.

So let’s look at it.

In 2012, Anthony Davis was the NBA draft’s first overall pick. He’s a once-a-decade talent. Fine. Let’s look at the top of the draft since then. I’ll list the first overall pick each year, and you tell me if you’d have rather have drafted that player or Barrett:

2013: Anthony Bennett

2014: Andrew Wiggins

2015: Karl-Anthony Towns

2016: Ben Simmons

2017: Markelle Fultz

2018: Deandre Ayton

So … I’d have taken Towns over Barrett for his inside-outside game at 7-feet. But I’d take Barrett over the other five, no question.

Point being, in the last six drafts I think Barrett goes first overall in five of them. And not as a “Well, he goes first but it’s a reach.” He goes first legitimately. And the Knicks will — presumably — be getting that player at No 3.

In what world is that not excellent?

When I look at Barrett, I see shades of Paul Pierce and Dwyane Wade in his game — and I see shades of Baker Mayfield in his swagger and competitiveness (everything you read and see with Barrett is that he’s a ferocious competitor). If you think the Wade comparison is too lofty, consider:

Player A: 22.6 points, 7.6 rebounds, 4.3 assists, 45.4 FG%, 30.8 3P%

Player B: 21.5 points, 6.3 rebounds, 4.4 assists, 50.1 FG%, 31.8 3P%

Player A is Barrett — at age 18 at Duke.

Player B is Wade – at age 20-21 at Marquette.

Sure, these are college stats and all that, but as The Athletic’s Sam Vecenie pointed out, Barrett is “the first high-major player to average 22 points, seven rebounds and four assists — and he did it as an 18-year-old freshman who re-classified into the 2018 recruiting class.” Frankly, that’s outrageous.

As far as testimonials? From The News & Observer in March:

— Steve Nash (Barrett’s godfather): “He’s incredible. It’s hard to believe he’s only 18 years old. Really his skill is he’s a fantastic passer. His size, at that position, it’s hard to compare. At 6-7, to handle the ball and pass like that is a skill that translates even more so in the NBA.”

— Mike Krzyzewski (Barrett’s coach): “He really is a good a passer as we’ve had and his defensive rebounding and then his leadership. … He’s become a better leader, rebounder, passer. As good player as he was at the beginning, I think he’s better right now. And he wants to continue to get better, which is kind of a neat thing.”

— Jim Larranaga (Barrett’s opposing coach, at Miami): “He plays so hard at both ends of the court. He is such an aggressive attacker. He does something that I’ve tried to teach my sons and my grandsons about basketball and that is, about 95 percent of the time the aggressor wins.”

We can play the you-never-know game, but off of everything you see when you watch Barrett play, everything he did at Duke and everything he offers — his size, his skill, his all-around game, his makeup, his competitiveness — there is so much to suggest he’s going to be a great player. He’s among the most polished and advanced freshmen I’ve ever seen.

Some criticism of Barrett seems to be he only shot 30.8% from 3-point range this season. What’s strange is, when there are questions about Williamson (surrounding his shot or his game beyond power/athleticism), people scoff and say, “Well, he’s only a freshman. It’ll come.” That’s certainly a reasonable evaluation — but why isn’t Barrett afforded the same alibi? Of course Barrett has flaws — he’s 18 years old.

Back in 1993, the Magic traded No. 1 overall pick Chris Webber for No. 3 overall pick Penny Hardaway. According to Sports Illustrated, the Orlando fans booed, so Magic GM Pat Williams addressed them and said: “Those of you who are upset, your jeers will turn to cheers. Your first look at Anfernee Hardaway will thrill your hearts.”

There are a lot of parallels here. Take Zion Williamson out of the equation — the bottom line is, the Knicks are getting a kid who has a chance to be a star. And probably a pretty good chance at that.

Mark Hale is The Post’s associate sports editor