So uh... Can someone tell me how old is the top? I got from the comments that he's an adul...

Nobody ever said his age in the comic, but he has said multiple times that he's an adult and he is old enough to drink apparently

He's probably 18 or 19

It never outright says his age but we know he had recently turned into to an adult, I had to got back and reread, but until chapter 35 when asked why he doesn’t take off his clothes Ever he says that ever since he has been using magic his body stopped growing and that makes him feel unmanly so he doesn’t like to be seen naked.

Eve has to be (at least) 20, since that's the legal drinking age in Japan.

This author also likes to draw buff bottoms paired with "cutesy" tops, usually with switched characteristics too - like crybaby/slutty buff bottom x sadistic/powerful but adorable looking top.

It's a popular sub-genre, and a common plot point you'll see is the buff bottom is *younger* then the cutesy top, but no one things so due to appearances. Someone is usually salty about it too lol (Idk if that'll happen here, but I wouldn't be surprised)

Noo he is so much older

Thank god, I just wish his body didn't look like a kid either

I feel like it's still a bit young because the bottom looks like he's at least 25 or something but 19 is better than him being underage I guess

That makes since, thanks for explaining

I'm all for smaller top/bigger bottom, it's one of my favorite things while reading bl actually, I just don't like it when one of them is a kid and all (or looks like a kid)

Huh. I think Eve looks like a petite adult, but maybe that's because my whole family is so short/baby faced ☠
I completely understand not wanting to read to interact with media involving minors/minor-coded characters though. If you're okay with a small spoiler, chapter 19 has a festival where you can see how the artist draws children (vs. Eve), and shows Eve standing next to Gozu and other adults. That might help you decide if you'd like to read it or not.

If you'd like a reading suggestion, one of my favorite manhwa's of all times is "The Third Ending". Both MC and ML are adults in their late 20s with careers, they look like adults (they're buff uwu), and it's a complete series!
The bottom has a cute personality/expressions while still acting like an adult (career, setting boundaries, having friendships outside of his relationship, etc)
...and the top cries very easily...while still being slighly obsessive but in a mutually consenting way (ФωФ)