There are some fine lines here. If you are unmistakably a member of the group being made fun of, you are less at risk of being perceived as using a put down because you are poking fun at yourself. Making fun of yourself is generally acceptable. For example, at the time of this writing I am 75 years old and no one could doubt that I qualify as a senior citizen. Later on I have a whole section on senior citizen jokes. Even though so-called ageism is frowned upon by our society these days, I can get away with telling jokes on us senior citizens. In fact, some of my best jokes are senior citizen jokes.