When is it appropriate to ask a crush out?

Mara • Bi // pisces // portuguese
We're the same class everyday, I know he likes me so it's just a matter of time. Things are a little awkward though, we don't get to talk a great deal irl but we speak on fb messenger.
I do like him, I think it's because we're both shy that it's a little awkward. He feels unsure to whether I like him or not because when he's friend asked me whether I was single for his sake (as he was shy) I panicked and said I don't do relationships. But I was trying to warn him and not come across as a rejection.
I decided I'd like to pursue something with him but its like it won't progress until we get time alone together irl. 
Ultimately, can I ask him now during the weeks holiday we have from college or is it too advanced knowing we've inky spoken for a few days?