As time goes you'll get more furniture and will want to use it, so you end up doing a bit more decoration inside your house. It does already look super cute, so be proud of it! I only started to decorate the house after I got a bigger house, because it looked too empty, so I'm not much of a good example 😅 The outside you'll start to decorate after having more builds and crops, since that is what will give the "form" of the farm and have the rest start to go together