Before you purchase a home, you need to choose the kind of interior design that you think work best for you. As an adult, you must understand that all options are possible. You never have to limit yourself, for as long as you have enough budget for it.
Now, if you want to live alone in your new purchase home then the kind of interior design that will suit you best is one that will make managing your everyday life easier. You may consider living in a home where there is no room or studio type. One that will not require you to clean a lot of areas. You can just install cabinets in spaces in your home so you never have to re-arrange it every time. You can also add some more decors just don't place too many types of furniture for it may eat a lot of space.
Nonetheless, if you are expecting some visitor from time to time and wanted to leave a little space for yourself then you may ask your interior decorator or anyone who is skilled enough to make at least a single room. By doing so you can at least keep a little space only for you.
Two bedrooms may work for you if you want some relatives or friends to visit you and stay at least for a night or two. You can also add few more bed in one room to make enough space for other more visitors. Just make sure that you still leave a space for you in the other room.