I think learning Android in 2018 is very exciting now as Google officially supports Kotlin and introduction of new set of libraries such as Android Jetpack. https://developer.android.com/jetpack/ By following newly introduced jetpack, you could avoid most of the deprecated libraries.

And going through the google architecture blueprints repo and sample https://github.com/googlesamples/android-architecture will help you understand how you should approach to your new apps development and help you get started in a right way.