How to keep a friendship?

I’m 23f, I have extreme social anxiety, (and likely autism) I feel like everyone hates me even my friend and boyfriend basically, even though they probably don’t. I never message people first because I don’t know what to say and I don’t want to annoy them or push them away. I’m really bad at texting.

I have a boyfriend but other then him, the only friend I have is my friend I’ve been friends with since we were little, we hang out once every month or two, she has friends she hangs out with often, but she doesn’t invite me to anything, so I don’t know if she likes me that much.

Im a really lonely person, as my boyfriend works every day and I only see him at night. I don’t work, or go to school so I don’t have contact with anyone else. I’m even too shy and anxious to make friends in games I play.

Yesterday I met someone who has a lot in common with me, they are so cool, but sadly live in another province. I got their discord, and social media’s and stuff. We messaged a few little messages, like sending memes and stuff, and I really want to keep this friendship.

How do you message someone first? What do you talk about? What’s a funny or casual conversation starter? How do you message someone without bothering them? This is the first chance I’ve had in 3 years to make a new friend and I really don’t want to blow it :( I’m afraid I’ll be too shy and it’ll come off like I don’t like them, and the friendship will fizzle out, it’s happened to me before. Please please give me advice if you understand 🙏