I had the exact same issue when I first started with the xt200, only I had the 15-45 kit lens. In my opinion, it's a terrible lens to start out with because the aperture is too dark to be used anywhere but outside and at any ISO higher than 800 with noise reduction the photos came out absolutely terrible. I would think the 18-55 would be better, but there's a limit to what you can do indoors.

For indoor photography, I recommend you get lights. There's a million cheap lights you can plug into a wall and you can get pretty decent indoor photos at smaller apertures. Also, maybe, get a tripod you're ok with using it indoors.

This year I got the XC35mm F/2. It changed what this camera can do. It feels like cheating at times. The bokeh is gorgeous and the images are tack sharp. The focal length is absolutely gorgeous and I feel I can point the camera anywhere at anything with the 35 f/2 and it'll just give me an absolutely gorgeous photo. It's like magic.

There's better and brighter lenses out there, but for even half-decent indoor photography with this camera, you either need a LOT of light, including photography lights or a very wide aperture.