I can kind of relate to you. I befriended some people who liked to joke around more often than me, and I tried with varying success to become a part of that world so that people would like me more, and because it seemed fun.
There's a lot of different aspects to being funny. There's not taking yourself too seriously. There's the physical comedy aspect of it. There's doing different voices well. There's having good comedic timing. There's being able to think and react quickly on your toes. Probably more areas of consideration than I have time to think of. You could focus in on specific things like this and try to determine if you have a knack for a specific kind of humor.
But I think one of the major things to keep in mind is that everyone has their own sense of humor. Personality, experiences and upbringing play a role in it. It could be that your sense of humor is different from your friends', even if you understand theirs.
I listened to my friends joke around and slowly tried to participate. It took a lot of trial and error, and a lot of times my attempts at joking around fell flat. At times like that, it pays to be friends with people who can shrug off small things and not be bothered by imperfection.
You do have to be able to think on your feet a bit, and find openings to say things. But that happens as you build your sense of humor. For me, I turned to puns a lot. I still was never that great, but I had a few good moments with it.
One good rule of thumb? Determine whether you are someone who wants to push boundaries or be liked. If you're the former, then nothing is sacred and your jokes should have no boundaries as long as they're funny to you. If you're the latter, you need to put a lot of personality into your mannerisms and cultivate a less-offensive brand of likability.
I hope this helps some!
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