I am doing a self study now a days. The topics are unfamiliar. Hence the question.
There are a number of things worth considering when choosing to set a deadline, but I'll focus on one: don't be too hasty to set the deadline.
If you aren't familiar with a subject, it will be very hard to gauge how quickly you'll pick things up once you get started. It's fairly reasonable to assume that you'll start learning faster the longer you spend time studying the same sort of thing, but you don't know:
Without knowing those things, making an estimate to use as a deadline just doesn't make a lot of sense. So my suggestion is to take some time working on the self study for a while until you feel comfortable with the subject matter, enough to say "Here are things that are easy for me, here are things that are hard for me, it took me X long to do Y, so I have to give myself more time for Z," and so on.
There are several types of deadlines. Sometimes you need to know the material by a certain date - then it is easy.
The others are goals/artificial ones to motivate you. One thing you could do with these before you know the topic is to have a goal of studying X hours a day for two weeks. Then at the end of the two weeks set a more content driven deadline.