Immature sense of humor?

So I'm 24 and have a pretty open sense of humor. Sometimes it would pass into what I would consider immature, but not often. But my girlfriend has recently been making me feel weird about my sense of humor and saying it is immature. I will give some examples of what she called immature and I guess this is kind of a double vote. Yes means these kinds of jokes are immature and/or abnormal no means they are not immature and/or are normal.

1) I'm straight, not bi, and one of my friends is straight as well but very uncomfortable about homosexuality. So sometimes I will fake flirt with him to make him uncomfortable.

2) Sometimes if I'm feeling bored I will think of random things to do to just to give people a laugh, one that she brought up as immature was writing on a different male friends' wall "I wrote you a love song today." and then just quoting a few bars from 'Drops of Jupiter' which he and a few other friends found amusing and went along with.

3) Sometimes if I post on a social networking site complaining about some behavior one of my friends will post a response emulating that behavior, to which I respond to pretending to be oblivious to it, and we go on for a few responses pretending we don't know what's going on. It's not to fool anyone else on my friends list, it's just to have a little fun.

Anyways, I don't see any of these things as 'immature' humor. I don't know what kind they are, but immature to me has negative connotations and implies fart jokes or something along those lines. Is this immature/abnormal for a 24 year old? And if it is not immature humor, what would you classify it as?