Round Tummy and smelly farts

I have a new kitten that I recently got from a non-kill shelter. She is 4.5 months roughly and she has this round tummy. I called the shelter and they said she was dewormed twice and has been given all her vaccinations and her spay on 8-8-13. I'm only concerned because her poo (eeek) is solid but it a lighter tan brown color and it has a soft serve type texture. She also farts A LOT and they smell. I don't know if its because the change of diet or if there's something wrong? Please Help!

It could be either change in diet, stress from a new home,  or parasites.  She could have parasites other than what they treated her for or she needs another round of dewormer.  They are sometimes a little stubborn to get rid of.  I would take her to the vet with a fecal sample and get her checked again unless you just got her within the last few days.  If you got her very recently give her a few days.  I got a new kitten that did that the first few days and she came out of it.

We had her for a little over a week so we think it might be worms

I would get her checked for parasites.  If it were stress and/or diet change she should be getting better by now.

Sounds like worms to me!  Often, kittens have to dewormed multiple times to get rid of all of them.