Proyect, I have a question

Proyect, I have a question - student project

It´s not my pet hahah, but I wanted to try the coloring thecnic.. And I have a problem. I used Photoshop 2019 and the selecction with the wand has changed.. I don´t know how to explain it haha,(english is not my firts language xD) the thing is that I made the line art and I wanted to select the fill (you know, the inside haha, like showed in class) but insted, it selects the fill of the line.. And I don´t know what to do. I don´t remember how, but I managed to select it but it maked the outside of the draw very ruff (like pixelated) and I had to retrace it with the mask on and it was like doble work. I looked in youtube for tutorials but found nothing. Hope someone could read this and help me. Thank you :)Proyect, I have a question - image 1 - student project