From personal experience, inspiration comes from great ideas & concepts. Some of my best work has been when a client has an idea that literally gets me excited.Around 7 years ago I started it up as a hobby and got pretty good at it. I then started a study for it 3 years ago and my interest in it slowly fade away. After passing my study I completely stopped with graphic design because it is very hard to get a job in it and I must say I like it as a hobby more. Even though I was the best student in each year I just found it very boring and quite easy to do. I'm the sort of person that seeks challenges. I still do some freelance work if I need some extra cash but I have no interests in doing more than that.
edit: oh I forgot to note, I can actually make anything its not a problem at all but I lack the inspiration most of the time, I was actually thinking for 2/3hours on my exam what I wanted to create, easily finished in time though but inspiration is definitely the most important thing to have for this kind of job So if you really enjoy doing this i'd say just go for it. Why the hell not? You'll see where the ship sails. Just follow your dreams even though people tell you not to