How can I be more outgoing around others?

Me and my friends all love music. We all play instruments such as piano , guitar , drums ETC. We like to Jam kinda. I think im a good singer and my family have said i am but when i want to sing in front of my friends I always end up singing in a joke voice. I think its a confidence issue. Also I think it is to do with for example i hear someone ells sing say in school it rely irritates me... probably because there confident... I'm not trying to sound arrogant and im not rely asking a question im just putting this out here for myself.