Guys, if a girl is nervous talking to you, is it a turn off or is it cute?

I noticed that there’s this girl who is much younger than me in yoga that I go to, and every time I talk to her, her voice seems to shake a bit, she speaks in a very low key tune, smiles a bit here and there… It isn’t necessarily attractive but I find it heart-melting. Even though she doesn’t seem so intellectual (who knows if she is or not).

I wanted to know what others’ opinion is on this!