I am still not getting any better with my tumbling!?

I Don't want to sound like a baby, but i have been taking tumbling for three soon to be four years, and I still am not even close to having my basics! I can fall into a bridge but i cannot kick over, i am no where close to having center split i also cannot hold a handstand for no longer than "1.03 sec." not to mention my front and backhand springs only exsist on the tramp. My goal was to be competing by now, and i still want to by the begining of next school year. My gymnastics coach says i have the skills but not the confidance, but i konw that is not true, I could use some advice. I am willing to work for it. Im not just expecting my skills to come to me, Thank you!