I feel like I'll never have friends

I have agoraphobia. I spent a good portion of my life inside, not really interacting with anyone. I have made TONS of progress and I'm able to go out and do so much more than I used to but I still struggle with social interaction. I so desperately want to have what others have. I want to be able to connect with people and form friendships but I genuinely don't know how. I never seem to say or do the right things. I see the way people light up when talking to someone else and it makes me sad that nobody seems that happy to be talking to me. I'm angry that my parents didn't notice when I was a kid and get help for me. Now I'm in my late 20s struggling to do something that should come naturally. I feel so alone.