Just go ahead and sing. I think of the amount of people who won’t sing out because they ‘aren’t good’, even though they do secretly love to sing. I was one of those people. Totally nervous and ashamed to use what is just beautifully natural and part of being human. I often joke that I’m still a guitarist who’s trying to sing but I also know my voice has come a long way. I’m no Freddie but it keeps improving and I just enjoy it more and more. So just go for it, have fun, sing your heart out, and over time you’ll improve.