So you suck at martial arts? You have no natural talent? Your balance is pathetic, you have no breath control, you are stiff and uncoordinated? That's terrific!
Go ahead and suck. I suck too. Everybody sucks. The question is not whether or not we all suck, the question is what we suck at and how badly we suck.
So you see a lot of students wearing black belts and they don't seem to suck. Trust me, they suck too. You just don't see all their mistakes, because your eye is not accustomed to looking for the details where they reveal their suckitude to their instructors.
What matters here is that we accept that we suck. It's OK to suck. Be awful, be useless, embrace it!
But keep one goal. As we train, we try to suck a little bit less each day. Not huge strides, small gains. It will sneak up on you, you will not notice it. Or you may notice tiny little differences one day and go "Hmmm, I used to not be able to do that..."
So we all suck and it's OK to suck and we're going to keep sucking.
Just suck a bit less each day.
Keep training. There is no one in the dojo who thinks you are the worst they have ever seen, because THEY were you a few short years ago. They have the benefit of hindsight which you do not yet.