Wow! Don't be discouraged!
Seriously, you ride better than most twenty-somethings my age who have been going snowboarding for years haha.
Keep it up! For inspiration, I met an old man earlier this year(86 years old) who said he picked up snowboarding in his 70's. He didn't go fast for safety's sake, but his form was great and I was thoroughly impressed by him. Told me at his age you just gotta take it slow and steady... and most of all be patient with yourself and it'll eventually sink in.