you know what? I'm the same as you.
I love singing, always have - but I have always been painfully shy.
I really, really, really wanted to sing in my church choir when I was a child - mum wouldn't let me cos she said i wasn't good enough (obv never having heard of training )
When I was 25, i used to meet friends of mine in the pub on a Tuesday evening, after tehy'd finished Choir Practice.
Then I started to get bored of witing (they never finished on time) so i started going along to practice with them. Just used to sit in and sing along (quietly until I knew the peices), then one morning, I went to churc hwith them, and I was about to sit in the congregation when the choir master shouted to me: "are you robing?"
I said "am i allowed?"
to which he replied "you came to practice didn't you?!"
and that was it, I was in the choir.
Still bloody scared about singing in front of people, but I loved it! 
and when I moved here about 2 years later, I swallowed my fear and approached the choirmaster of my new church, and went along to practice that week.
I started doing the Voice for Life scheme, and in it you have to sing solos . 
And now I can sing solos, in front of people, in front of lots of people.
and It's been the best thing to cure my shyness (still can't talk to people, but I can sing in front of them!)
the best thing you can do is go along and merge in with the other singers of your voice, and eventually, as you get to know what you're doing, you'll be brave and sing out like you're made to!