setState delay in React Native

I just have a short question about onReady in React Native. I want to use it like this:

<View style={styles.main}><ReelSet ref={(ref) => {this.reelSet = ref;}} onReady={this.onReelsetReady} /></View>

ReelSet is my component. It doesn't come with React Native.

Its has a function called spin (I point out the if-statement below):

  spin = () => {    this.reelsInMotion = Constants.REELS;    for(let i=0; i<Constants.REELS; i++){      this.reels[i].scrollByOffset(this.randomBetween(        (Constants.REELS_REPEAT - 6) * this.reels[i].symbols.length,        (Constants.REELS_REPEAT - 5) * this.reels[i].symbols.length,      ), (reelIdx, results) => {        this.reelsInMotion -= 1;        this.spinResults[reelIdx] = results;        if (this.reelsInMotion === 0){          this.evaluateResults();          this.props.onReady(); //<-- This takes about 2 seconds        }      });    }  }

While this.evaluateResults(); works on time, this.props.onReady(); needs some time. This is because of setState in my onReelsetReady function.

onReelsetReady looks like this:

onReelsetReady = () => {    this.setState({      spinButtonActive: true,      loadingVisible: false,    })    console.log("debug");  }

Why does setState need some time to change the states? I have the same problem here:

this.setState({  credits: this.state.credits - 15,  spinButtonActive: false,}, () => {  this.reelSet.spin();  console.log("Spin")});

react-native info output:

    info Fetching system and libraries information...    System:        OS: Windows 10 10.0.18362        CPU: (8) x64 Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz        Memory: 6.78 GB / 15.67 GB      Binaries:        Node: 12.9.1 - C:\Program Files\nodejs\node.EXE        npm: 6.10.2 - C:\Program Files\nodejs\npm.CMD      IDEs:        Android Studio: Version  3.5.0.0 AI-191.8026.42.35.5900203      npmPackages:        react: ~16.9.0 => 16.9.0        react-native: https://github.com/expo/reactnative/archive/sdk37.0.1.tar.gz => 0.61.4

expo --version

3.17.23

If there is any solution, I would be glad if someone could post it.