This is my first attempt at colorizing a full pice.

The black and white manga was used at a 50% opacity to show the colors of the layer underneath.

I used this translation /g/1838184/0e62752095/

Eddit: used darken to fix text.

This is really well done. 2 criticisms though:
Some colors are far brighter than they need to be. The uniforms and backgrounds are very distracting, for example. Go for something more realistic.
If you can select regions of the image to change the opacity on, then keep the translated text elements and panel frames at 100%. They need to be solid black. It will keep the image from looking too washed out.

Base +6, Nartousamaci +6, viniccius36 +5, Guyintheweb +4, Zelalinz +7, AininChase +6, BLKVMP +6

The coloring would fit a more cartoony or stylized doujin but it doesn't fit Mashiro Shirako art at all, you tried to be too faithful to the color temperature but what works in black/white doesn't work in color, so this kinda feels like a children's coloring book, take a look at the covers/color pages done by the OG artist.

Base +6, Nartousamaci +6, Guyintheweb -4, Zelalinz +7, viniccius36 +5, Metal_splurge +6, ZIGMA44 +15

nice coloring... love it...

Base +6, Guyintheweb +4, jjaysenea2003 +6