Just forget about parrying it's too intricate for a beginner, if you see a low coming - block it and try to punish while theyre in recovery frames. You will be more consistent +simply blocking is at times better than parrying because you can get actual launches off it which lead to more damaging juggles.

Also you didn't mention that you do this, but I assume you do because all newbies do it and it makes me facepalm. You probably use moves when you can't reach your enemy hoping that he steps into them - don't. Try to learn how far each move you use can reach, this very important because otherwise you are just leaving yourself vulnerable for nothing.

Keep trying, if you've stayed for this long you're probably going to see significant(relatively) improvement soon. Just takes time to get familiar and apparently some need more than others. And once you do get it, it's something you'll always know from then on, even if you put the game down and return to it years later it will all come back very quickly.