There's a moment where Paul's looking at Chani like he's a dumb lovestruck puppy and the sound mix actually fades her speech out which kind of feels like it should break the tone, but doesn't. I think that's because we're very much in Paul's perspective (hence we join him in tuning out what Chani's saying because he's caught up in looking at her) and there's a sense that he hasn't actually experienced this before. Whether that's puppy love or something deeper, which this very quickly becomes.
It's left implied where the book was explicit about it, but Paul's circle of friends was really confined to his teachers and immediate circle of protectors, without any friends or confidants his own age or the opposite sex. That's not to say that he wasn't cared for, because Thufir, Gurney and Duncan clearly do, but it's not particularly conducive to having an ordinary childhood. Romance, in particular, was not on the menu.
So despite the fact that he's running round blowing things up and hiding in the sand for hours at a time waiting to shank Harkonnens, Paul's time with Chani is the first time he really gets to just be a teenager. And it lasts only a matter of months before he has to take on memories of pain and sorrow going back thousands of years, and in a sense very much ceases to be a young man.