BEAR, Del. -- It has been a busy day in the McKenzie household; that's only natural when there are inhabitants ages 20 and younger. One of them, Mark, just so happens to be a second-year center-back with the Philadelphia Union and one of the rising stars within U.S. Soccer. But it's another McKenzie who has the more pressing matter. Younger sister Madison has prom coming up and a decision needs to be made.

"Sorry I'm late," says Mark, who slides into a booth at a Buffalo Wild Wings, just miles away from the McKenzie home. "I had to help my sister pick out her prom dress. It's a big deal, you know?"

The same could be said for Madison's big brother. In the past 12 months, the 20-year-old made his MLS debut, started 18 matches, captained the United States Under-20 team to a first-place finish at the 2018 CONCACAF Under-20 Championship and then earned his first U.S. senior national team call-up. Not exactly normal stuff for someone who still can't order a beer with dinner.

He's yet to play for the Union in 2019, but McKenzie is expected to start against Montreal on Saturday (1 p.m. ET, ESPN+). It will be the latest step forward as he prepares for this summer's Under-20 World Cup.

"The last year has been great. There were a lot of ups and downs but it's been a learning experience," McKenzie says. "I just wanted to put my head down and do my work, and ultimately, I feel like my play would do the talking and it did. It's been a whirlwind to keep it all together, but I'm extremely humbled and thankful for what happened last year."

On this night, however, McKenzie is like any U.S. fan experiencing the emotions that comes with watching the national team, this one a late March friendly against Chile. There is praise for Michael Bradley ("Dude, I picked his brain so much during camp") and Gyasi Zardes ("That first touch bro, how 'bout that?"). But there is also angst when Chile equalizes. ("Argh! Can't let that happen.")

One of the biggest takeaway from watching the Chile game with this budding U.S. star is that McKenzie is a true student and lover of the game. He'll sit there and patiently wait for your reasons as to why Lionel Messi is better than Cristiano Ronaldo while munching on his sandwich, and then counter it with his own in support of the Portuguese superstar.

He'll also wade into waters that divide much of American soccer. Promotion and relegation? "We need it. We need that incentive so we don't get complacent." That night in Trinidad in October 2017? "It was a sad night. So much buildup for a big game and to see it crumble hurt me personally, because I'm part of it in a way."

McKenzie has a passion for other sports, too. His occasional glances at the other televisions in the restaurant reveal as much. The NBA is a favorite, and while he enjoys watching the games, it's the off-court stuff that really gets McKenzie's attention. "NBA Twitter, man. It's so petty! I love it," he says with a laugh.

Even if he's held out of this summer's U20 World Cup, Mark McKenzie has a bright future with the U.S. Philadelphia Union

McKenzie is also a big follower of the NFL. MLS locker rooms boast players from around the world, which means players from overseas make for prime targets when it is fantasy football time. Pity the new foreign arrival who decides to join the Union's league. "I'll say, 'Yeah bro, Ryan Fitzpatrick is a solid choice,'" McKenzie says, drawing laughs from the two Union staffers across the table.

Just as easily as McKenzie jokes around, he is sincere on other topics. One such discussion in which he finds himself in the middle is whether he'll be in Poland this summer with the U.S. at the U20 World Cup. It all depends on the Union releasing him for the tournament, and of course getting selected by head coach Tab Ramos. The look in his eyes shows clearly that McKenzie adores his time with the U20s, fondly recalling the 2-0 win against Mexico in the 2018 CONCACAF Under-20 final.

"That game was so much fun, I just kind of sat back and watched Paxton [Pomykal] and Alex [Mendez] run the show," McKenzie said. "You know, you spend the whole month together, and when you spend that much time together, a bond grows. I talk to a lot of them sometimes on a daily basis. We'll get on Snapchat and comment on each other's tweets or Instagram pics. I'm really tight with those guys."

It's also a situation that has the potential to serve as a headache for Union boss Jim Curtin if McKenzie is not released for the tournament. The last thing anyone wants is for a bridge to burn between player and team.

"It has to be what's best for the Philadelphia Union, what's best for the national team and most importantly what's best for Mark at this stage of his development," Curtin told ESPN FC. "He's a big part of what the U20s have accomplished, he's worn the captain's armband because of his leadership. We need to recognize that it means a lot to him. We'll see where we're at as a team health-wise, fitness-wise and where Mark is in the group."

While not making the trip to Poland would be disappointing, McKenzie gives off an air that bigger things are headed his way. Driving that is his unquenchable thirst for knowledge. As the U.S.-Chile match drifts into the second half and the food has been cleared away, the conversation turns to his life away from the field and non-sporting interests.

The void of not being in college like many 20-year-olds is being filled by teaching himself French and German. There is also a casual mention that he is learning to play guitar and piano. It's all very impressive and it doesn't come off as boastful. If anything, it is spoken with a confidence that reinforces his desire to feed his brain, something that teammates notice daily.

"After training he'll come back and he'll be like, 'Remember that situation, you want me to shift over a little bit, you want me to step?' And we'll talk through it," Union midfielder Alejandro Bedoya told ESPN FC. "He's always learning and that's what you want out of a young guy, always asking questions."

At the dinner table, the conversation is briefly interrupted by sister Madison, who just happened to swing by to say a quick hello. The dress Mark saw is a finalist for selection, and Madison's date has apparently been properly vetted by big brother -- he is a defender, of course.

Madison's cameo is a reminder of the strong bond that exists within the McKenzie family and has emboldened Mark to wield his influence as an emerging African American player in MLS, serving as an ambassador for Future Soccer Stars, a local nonprofit that brings soccer to inner-city kids. When McKenzie is with the kids, he is present in every way: spending time with them, talking or playing soccer.

This commitment to community is nothing new, though. If anyone watched McKenzie take part in MLS' Black History Month roundtable, they found someone who has long thought about what it means to be an African American in this sport.

"I'm proud to be black," McKenzie said. "I think you see so much negativity, so much racism popping up here and there in this game, so if I can stand up and speak for a broader audience, and be a face for those who may not want to or have the courage to speak up, I want to inspire them to raise their voice.

"I don't want it to just be a conversation, I want there to be action. I want to see others involved in stuff like this. Off the field I feel like this is something that we need to be proactive about and that will grow on the field."

As with any international friendly, the number of second-half substitutions has disrupted the flow of the game, and now less attention is being paid to the USA's fate. Free to head back home to rest up ahead of another day of training, McKenzie instead waits around to make sure that this author and first-time visitor to Delaware isn't standing by himself while waiting for his ride. It's a small but thoughtful gesture that encapsulates the positive vibe that McKenzie emits both as a player and a person. The next morning at Union training, Curtin smiles when the previous evening's activities are retold.

"That's down to how good of a person he is and how good his parents are," Curtin said. "With Mark, the sky's the limit. I'm really proud of his accomplishments on and off the field. It's been fun to watch."

Make no mistake, big things are headed McKenzie's way for club and country, and even bigger things in life.