I’m the second youngest of nine siblings, but I’m the the tallest by far. Little and baby are used endearingly, not as a sign of actually age. A few other families I know do the same.
 
Not to say that it offsets the confusion, but it happens.

Baby sister? she the older one! a mistake!

@Ammit5  
Zep needed some tough love, and I glad that it helped him improved.

Continuity errors and awkward character models aside, it’s nice to see Zephyr and Fluttershy have a friendly sibling rivalry going on now. I always thought Flutter Brutter was a little too harsh on him.
 
_{and hit just a little too close to home…}

@mjangelvortex  
Most people thought he was older until/unless they learn that he’s the younger one. Again, Big Mac and Shining Armor being the only other Mane Six bros and both are bigger and older doesn’t help prevent mix-ups either.

@Meanlucario  
That too. He’s pretty tall so it’s an easy mistake to make. I thought he was older than her at one point before watching the episode.

@mjangelvortex  
That and both him being bigger and every other Mane Six bro being older doesn’t help things.

@Background Pony #6D42  
The people working on the comics have made continuity errors before a few times.

>baby sister
 
Dude, Fluttershy is older. WTF.

@Background Pony #AEEC  

@mjangelvortex  

I kind of wonder if that’s a nod to how he’s improved since he was first introduced. A more confident Zephyr who feels like he can actually succeed on his own might just want to look the part too.
 
Or maybe he just does better business if he doesn’t look like a bum. Could be that too.

He looks so much better without the beard.

@Background Pony #C9E5  
She’s his “little” big sister.

@Ammit5  
This (as best can tell) an established comic artist doing her first work on MLP. Consider Tony Fleecs’ first stories eg which you can tell are just a bit uncanny-ily off , but he’s gotten better. I dunno what Kate Sherron’s long term plan is for MLP but give her a few issues and it should be okay.

The character designs look a little weird here. Make no mistake, I’m glad Zephyr finally learned how to shave, but their facial shapes and general proportions are way off model. Yona in particular seems unusually hueg in the top panel.

@Background Pony #C9E5  
Gee, they’re almost insistent about it.

Actually they mention it five times, not four. Lol

@Masem  
Actually, no. They mention that Fluttershy is the oldest four times in the episode. I’m very disappointed with the people who worked in this comic and do not play attention to that. When I read Zephyr calling her big sister “little sis” I knew that they really forgot that he is the youngest.  
If you would like to see the quotes here it is:
 
Zephyr Breeze: Guess who’s home! That’s right, big sis, it’s your one and only favorite little brother, moi.’
 
‘Zephyr Breeze: Hi, Flutterbutter! How’s the bestest big sister ever? Hey, where’s the love? How about a little excitement to see your baby brother?’
 
‘Fluttershy: That’s what big sisters are for.’

@Masem  

 
Like Mario and Luigi.

@Dustcan  
My though is that if you are not wholly familiar with MLP, and told “these two are brother and sister”, calling Zeph older makes sense due to height.

Finally, an image of Fluttershy sticking out her tongue at someone. Especially at her brother.

@Masem
 
Or maybe he’s taking a jab at her height.
 
Probably is a flub though.

@MangoBox  
Yeah. Minor mistake since that’s literally one line from the episode that establishes their relative ages.

Isn’t he the younger brother?