Google's first-party IDE for Android app development, Android Studio, is very powerful, but also fairly power hungry. Improving its stability and consistency has been a challenge that Google is addressing with its Project Marble initiative. Today's change is part of this initiative. Google will deprecate support for 32-bit operating systems in Android Studio by the end of next year.
If you've ever worked with Android Studio, then I'm sure you'll agree that running it on only 4GB of RAM will not provide a very pleasant experience. You'll definitely want at least double, if not 16GB minimum, on your machine to use the IDE efficiently. In order to make use of all that RAM, you'll need a 64-bit operating system and the 64-bit version of Android Studio. Therefore, Google will deprecate 32-bit OS support at the end of this year and will completely end support at the end of next year.
It's good that Google is giving those developers time to migrate to a 64-bit version of Windows. Doing so will enable developers of native apps to build 64-bit versions of their apps, which will soon be required for publishing on Google Play starting August 1st, 2019.
Source: Google