We know that making fun of others should not be done. But how about making fun of myself or let's say roasting myself? Is it haram is Islam?
Yes, it is just as discouraged. Your brain and body work as a unit. One affects other. When you speak something negative, it affects your brain in an unwanted way. Just as an edible can either be good or bad for your stomach, your thoughts and words can be good or bad for your brain. Ultimately affecting your brain and body respectively. Wrong things are not to be spoken or thought about or even remembered.
The rule in Islam is: other than specific things which are haram, everything is halal.
That does not mean making fun of yourself is a good idea. In some cultures, self deprecating humor is common and expected. In some cultures, you may confuse everyone.
The nature of humor also matters. You can end up harming your own psyche. Sometimes a little bit of humor can be a good deal breaker.
The best thing would be to avoid humor which shows anyone in poor light. However making fun of yourself is not haram.