@Hereward
 
I guess it kinda depends?
 
Because if you think about it, if she grows with her ego, the more she grows, her ego would get bigger as she does.
 
Cause you gotta thing about all aspects. If she grows with her ego and her ego grows with her, it would give her a constant reason to brag.
 
Bragging = Bigger ego
 
Bigger Ego = Bigger size
 
Bigger Size = More bragging
 
So on and so forth. It all makes sense if you think about it.
 
Just think though, she’d be a really big pony. She’d have a constant reason to brag.
 
I wanted to reply because that was a good comment/question. I’m really late though. Doesn’t matter.
 
Have a good day. :>

I’ve just read a chapter in a fanfic that has an OC describe Dash as having ‘an ego as big as Canterlot’. If Rainbow’s ego grows when she finds herself growing, then just how big might she get?