Can't text people, too nervous

I didn't know what to put this under. I think my inability to text people is due to my social anxiety so I thought I'd put this here.

I'm desperately trying to make friends and I'm actually somewhat doing it. I see them at lunch everyday and talk to them, but never text them or see them outside of school. I want to text them to get closer to them but I don't know how. I never know what to send them or keep a conversation going with them.

I can't ask them about school work either because they know I'm always on top of my work and I get it done all the time haha. So I don't know any good conversation starts or how to keep one going. To top that every time I hear my phone go off I get extremely nervous. I feel like whatever I send people they think its dumb and they judge me for it and that they're just putting up with me.

So any advice on texting people, how to do it and how to be less nervous doing it?

just do it. thats my only advice. it made me really nervous too at first but after a while i got used to it. everything makes me nervous though and if i get out of the habit of doing something then its like i have to start all over again.