Riyeko

So... im relatively new to the boa world I guess, ive had Eve since April of this year, since she was born in march and the guy said she was ready.

One of the things my husband has been concerned about is that shes not growing properly.
She seems to always be skinny and more.. vertically "fat" than round like a snake should be, and she hasnt gotten any longer (noticeably) for about two months.

She has shed and eats regularly, and we have begun feeding her from our rat stock (baby rats make her happy), but she still looks the same.

The only reason I think my husband is concerned is because a month and a half ago, i bought a year and a half (maybe 18 months), old male boa, thats a hell of a lot bigger than Eve (were talking, possibly 10 times bigger) and rounder.

Is there a reason she looks skinny? I mean, we have fed her smaller meals lately, and more of them, and she takes every one.. but wont take a second like shes full.

Do boas not "round out" until later on in life?
Do they go through some kind of growth spurt or something around a full year of age that makes them big and round?

Or is my husband and I just freaking out and questioning our practices for nothing?

Any suggestions and ideas would be most appreciated. Thanks!