Oh you're just shy. Haha sweet kid, people don't think your gay. Hell naw either they know your shy or think your a weirdo. Most people unless they're 14 wouldn't think a guy is gay because he can't speak to a girl, 80% of men can't speak to girls properly either I'm one of them.
Just stop focusing on them as being girls. They're people who have ambition, and a life just like you. Try and keep everything platonic, avoid thinking about how you could sweep her off her feet wit the right words,
I think people think you're gay because you're anxious about them thinking your gay, so you probably act how a guy who's not trying to show he's gay would act. Which in itself would always seem a bit weird or gay,