I try too hard to fit in and now I feel guilty?

So I auditioned for a band that I am very very passionate about and I have been placed on a trial basis. I would give anything to be in this band, and the leader told me that the personality was the number one thing. If I didn't fit in or click, it wasn't going to happen. And since then it has been about three weeks and I asked him how my trial was going, as in that time we'd played a show and shot a music video together, and he said that so far I was doing great. His only problem was that I tried too hard to fit in and be funny, and sometimes I end up sounding like a jerk. Musically he said I was 'impeccable' but it was just that aspect I had to work on.

I moved to the city of Sydney from regional NSW to join/form a band about two months ago and in this three week period I've had to adjust to this very new environment, where previously I had only been exposed to one group of friends for the last 8-9 years. And in that group of friends it was natural for us to insult one another and only joke about it, however I fear that because of that I now find it difficult to adjust to other social situations. I told him this, and he said its all good, and he's sure I'll sort it out. To me that does not sound promising. And now because I have an over active conscience, his words reverberate around my head all the time and I dwell on it and the more I think about it the more I realise how true he is and that I do unintentionally come off as sounding like a jerk sometimes when trying to joke around and fit in. This coupled with the breakdown of my first long-term serious relationship and general pressure of a new job I feel like I'm losing control. I want so desperately to be part of their 'brotherhood' and to be a part of their band, and now I'm afraid I've done too much damage with unintentional words to continue. What do you think? Is this salvageable? And is there any way to put over active and over guilty to rest about this?