When designing filters or options, for results or data always one thing comes to my mind is it has to support even if some more features added or removed later on. It must not hurt the design i am going for.
I will like to share my experience and views on same as below:
1. Following Your Design
Your design has nothing wrong, but could be more attractive, if you do not make it grow and do instead something else. You could always have colors to make things stand out from others.
You could fill the selected button or option by filling it with color or can say adding background color to it based on your theme. Something like this:
- It helps user to understand what they are having as results along with that not disturbing their eyes with growing up button, which may take their huge attention. Also if the results are not going to be same screen, you can make the selected button color brighter and more attention seeker.
- Above point was present, let's talk about future. If thinking from development point of view, if later you are enabling to have two buttons to be selected at same time. Growing two buttons is again less acceptable than having it colored.
2. Not Following Your Design
There are many options, and this answer could get more long than anyone can think of. So sticking to your point and requirement let's see below two examples:
Google Images: When search for Hotel Rooms, like any other image search results it has many filters or options to show and let you select, but they let you select also multiple. Which even if you have in your case, it would work.
Link Here to above View
You can select those filter buttons to get what you want. What happens after selecting is important and is not bad.
Link Here to above View
Using colors what they did is something opposite, made the selection more simple. But it still stands out among other colorful buttons.
If you go through Airbnb Website they have more options and filters but at some point they are using colors or had to use colors to make it happen.
Check "Home" being highlighted also "Room Type" being highlighted.
Summing up with showing too many images, is that the best option would be using colors in your case too and if you even change your design it remains same. I am not asking you to copy these designs, but to understand the meaning of doing it and the reason behind it.
I hope my answer helps you in any possible way.