Well now, if you just want to get there and experience the effect of singing with your peers, of course it is OK. Folkies are nothing if not tolerant.

However - if you want to get the maximum from yourself, put all the expression, physicality, artistry and sheer pizzaz into a performance - well the world is your oyster - if you can maximise the mindspace by having the words/tune memorised. Visual duties require huge amounts of brainpower that could be released, hence the tendency to close one's eyes when singing. If you point your head downwards the sound doesn't project in the right direction, it alters the larynx and muscles around the neck.

As a singist - the choice is yours, but it is not easy weaning yourself off the page, but the rewards are more than worth it. Make it your goal rather than the starting point.