I do not see the window of the android emulator in ionic. part I

I start creating my first application with the sentence: ionic start RedditApp tabs . Then I move to the directory of the new application, entering in my console cd RedditApp . Then I try to run the application by typing ionic serve . Then enter ionic cordova platform add android . Then enter ionic cordova build android , then ionic cordova emulate android and the emulator window does not appear. In the video tutorial I'm following if it appears for ios (I've also done the previous steps for ios)

My ionic info:

cli packages: (C:\Users\Familia Baldán\AppData\Roaming\npm\node_modules)

    @ionic/cli-utils  : 1.19.2
    ionic (Ionic CLI) : 3.20.0

global packages:

    cordova (Cordova CLI) : 8.0.0

local packages:

    @ionic/app-scripts : 3.1.8
    Cordova Platforms  : android 7.0.0 ios 4.5.4
    Ionic Framework    : ionic-angular 3.9.2

System:

    Node : v9.11.1
    npm  : 5.6.0
    OS   : Windows 7

Environment Variables:

    ANDROID_HOME : not set

Misc:

    backend : pro

And this is a screenshot of my console after writing ionic cordova emulate android

Viewing a question previously published I was also on ionic emulation , I have learned that I do not have to write ionic serve first, so I do all the steps described above and I find this information:

Does anyone know what is happening?