Indecisive with typing? (rant)

So I have tried online role-playing, mainly over Discord or Skype. It's like Dungeons and Dragons.. But.. I think my brain is getting in the way.

Basically, I'm terribly indecisive. I probably hit backspace more than I hit letters on my keyboard. And what it takes me 5 or even 7 minutes to type, they literally take around a minute or two. I feel like my granny looking at a computer for the first time. And trying to type.

That's how my speed feels. I understand you there gran.

But yes, basically I'm looking for how to get better, and stop being so indecisive. I read my paragraph (or half a paragraph) and think "No this looks childish" or "This makes no sense" and it takes so much TIME. So much friggin time.

Why am I like this? How can I fix it? (And yes I also have this stupid diagnosed anxiety, which is very often triggered in social situations. It's annoying, and probably part of the problem too.) :/