Bult a Ramp, could i make it better?

Use plywood. 

Built just an L-frame. Then hang a string to get a nice curve. Adjust the length of the string until you get the curve that you like. 

Trace the string onto plywood that you’ll use for the walls. (Or use multiple 2×4 studs) And cut that curved ramp shape out. 

Run 2×4 studs across. 

Cover with plywood.