Analogue to digital signal graph

I star‌ted the digital electronic course on youyube recently and i am new to the signals concept
In the pictures below i tried to convert an analogue signal graph to a digital signal graph
So first i converted the analogue graph to a discrete time signal graph as below

And then i quantized the value into four quantization levels
As below

Is this the right way to convert an analogue signal to a digital signal is my drawing correct?