Unless the candles go all the way around the cake like they normally do, in which case she’s at least 31.

@Background Pony #1393  
I looked over the episode transcript. They reference “Sleepless in Ponyville” as their last trip, but they only say year when planning the next trip after this one. It’s possible they skipped a trip between seasons.

@TexasUberAlles  
No, we didn’t. You can think that if you like.

remember that she celebrated her birthday and also her arrival in Ponyville

Didn’t we eventually agree– one of the eighty thousand other times this was previously brought up– that the candles all around the cake accurately reflect her age in moons or horse years or something? Time is not editorially intended to be accurately trackable in this universe.

@Wildcard71  
Ok ever candle with cake behind it count twice that’s 14 x 2 that 28 then add the candles that have landscape or sky behind them because their is only one of each of these totaling 7 so 28 + 7 = 35

@Ghost of Zeon
 
Estimated only 40% not showing!

@Background Pony #1393  
Half candles are not showing

@Evil Emperor Proteus  
Well, they did say in ‘Baby Cakes’ that they do tend to put candles on a cake to equal their age.
 
Also, Pinkie Pie said she was born on a Tuesday, and Hasbro said on Twitter her birthday is May 3rd, meaning she was most likely born in 1994, this episode aired in 2014, meaning Pinkie Pie was 20 at the time.
 
Also, Fluttershy said she’s a year older then Pinkie Pie, making her 21, the same age as Rainbow Dash according to the Cake.

I don’t think that means her age. Do you really think they put the candles only around one half of the cake? It’s actually not that common to put a number of candles on cake relative to the age of the person. Thinking she is 21 because of this shot is very simple-minded, primitive deduction.

@Background Pony #1393  
nope

@Flutterpest  
Yeah she 35 the others mane 6 member and probably Trixie and Starlight are about that age give or take a year or two.
 
But sunset was shown in her background comic to be as old if not older then Shining Armor so she is probably 40 at least.
 
The creepy part is Sunset and Twilight both liked and one dated the human Flash Sentryho is at best 15 or 16..
 
See what I was saying now?

@TexasUberAlles  
What?

THE CYCLE NEVER ENDS  

@Ghost of Zeon  
So are you saying Rainbow Dash is 35? And I don’t understand the rest of it

Actually you only counted half the candles. 14 candles have cake behind them assuming the cake is round and candles are evenly spaced. The each of those candles should be counted twice so her age should be 35. That actually makes seance for her and her friends to be around that age.
 
The real shock comes when you realize that Sunset is at least ten years older then Twilight and her friends in Equestria posting her in her 40s in the body of a high schooler who has confirmed to have dated a teenage boy in the first two years of high school. Yeah… the same boy the 30 something ponies princess Twilight danced with.

Rainbow being 21 seems plausible to me.

@northern haste  
If I recall correctly, they said it was their second camping trip and referred to the other one as ‘last year’.

@ABronyAccount  
SERIOUSLY?

WTF O.o  
“Stan Lee’s Mighty 7 Premieres”…….  
THIS SCREENCAP IS OVER 4 YEARS OLD OMG!!!!!

@Background Pony Number 17  
@Flutterpest  
Actually, it’s 41 candles since there’s only one candle on top and not two.

@Background Pony #12AC  
41 candles, actually, assuming a 3-d cake and we’re only seeing half of the candles + the one on top.

@Kolbjorn  
So are you saying they put candles on both sides so Rainbow Dash is 42 or is she still 21?

@Background Pony #12AC  
If the candles are placed symmetrically, you’re right.

No, she doesn’t have a canonical age. None of the mane 6 do. Those candles are b.s. and if they’re not, then Dash is actually no younger than 36, or did you forget that cake is three dimensional and in the very next shot she’s making circles around it to blow out the candles.