Hello Rady, this is a great first BAT. I'm really glad to see all the little details that you have added to the walls, roof etc. It really makes the model very interesting.
However, this model is still underscaled on the z axis. The sims - giants that they are - are taller than your barn doors

I would recommend scaling it up by at least 20% (I'm aware this is only supposed to be a small, 1.5 storey barn). The width is fine, but the BAT is a little shallow; once you have scaled it on the z axis, you may have to tweak the depth as well.
I would make sure that your first floor is no less than 4.5 meters tall. This will be larger than the single storey low-wealth Maxis homes that you are comparing it to, but will fit in better with most of the content (Maxis and custom).
Additionally, as Girafe mentioned, don't be afraid to dirty up your textures in photo-editing software. At the moment, your roof texture doesn't really blend in with the textures around it and certainly doesn't render the same in game as in your viewport previews.
There has been much talk over the years on why and how to fix textures (so I won't go into the details here - a search of some of the many BAT tutorials will yield results) but suffice it to say that all textures need tweaking prior to using them in the BAT
I have taken the liberty of making a couple of very minor tweaks which took only a moment or so:
* Desaturated the texture by about 20%
* Added a russet/brownish gradient
* Made some very quick dodge/burns
All up it took less than a minute, and was done in the GIMP - a free tool.
You could add moss, water stains and so on. The same could be done with the walls: but the results will definitely allow your barn to fit in with the games' pallette
Good luck
