There are a lot of places that are available near the MTR however you need to consider:
- Budget
- Plus are you fussed about the commute from home to places you will frequent daily.
Hong Kong is by far one of the safest places on the planet!
Whether you share a flat or not would depends on your comfort level sharing living space with another person. Personally, I think having a flat mate for a few months is not so bad as it can help ease the stress of moving to a new place if you move in with someone who has been here for awhile as that person is already familiar somewhat with the area.
Keep in mind your budget helps to determine the size of the living space you can afford. Plus, HK has some very small living spaces.