Good question.
In my experience about 90% of design students still don’t know what they specifically want to do in design after finishing their Bachelor’s.
Many end up doing something completely different. I see a Bachelor in design more as an exploration, while developing the necessary skills, vocabulary, and some depth in the plenitude of design areas. In the process you develop some affinity and an awareness of where you may head towards, but none of this is probably definite for most people. There are some who are more straight-forward and specifically state what they want to become, but they may in the end lack the broader awareness to implement truly innovative concepts and working methods. There are pros and cons to all of these differences in people but in the end there is nothing to worry about and you will find your place.
What is important is that you set specific goals for yourself, follow through on them, enjoy everything in the process and develop a sense of where you want to head towards. And if things are not going in the direction you expected, make sure you understand the situation and then take action - spin it around, push the envelope a bit more, do something radical, or just leave and go do something else. You take the initiative.
I don’t see a niche as something you have to find, but I do see that most people want to end up somewhere where they truly feel they belong, and in the end yes, you will be doing much of the same work with the same people in the same way. So it’s good to actively develop a sense of what this will be for you. For me, I have a good sense where I am heading towards but I also know I can’t force myself to already be there. I currently work in many areas of design, sometimes because it is a good fit to my skills, sometimes because it is conceptually in line with something I would like to do in the future, sometimes it is just because I can do it and it pays, and some projects are just a lot of fun. A lot of things come onto the path but I keep evaluating and heading towards where I feel I want to go. In the process I naturally pay less attention to projects that are less in line with this and more to projects that fit me better. This year I am looking to profile myself more specifically and develop an own product, possibly a kickstarter initiative, that may lead to a more specific career niche. I have always felt I am not an inventor or engineer, or an industrial designer in the classic sense of the term, but a designer somewhere along the lines of people like Daan Roosegaarde. I would like to develop interactive products that rather than introducing completely new innovations, change the way people interact with their current environments. So far my brainstorms and explorations have so far not yet resulted in the vision that I want. So all I can do is keep working and reflecting on it as much as I can.