Same thing happened to me in 2015 when I started learning iOS development. Apple announced Swift programming language in 2014 WWDC. At that time, I didn’t know both Objective-C or Swift. Most of the senior programmers recommended me to learn Swift. It wasn’t too difficult to learn swift since I already knew Java. But it was painful to read through documentation because the swift community wasn’t large enough.
And most of the libraries were written in Objective-C. Although I could use those libraries without knowing Objective-C, I wasn’t able to change them.
So, if you are new to programming or you already know java, stick with Java for a while. Learn Android apis, components and architecture first. Understanding components and their life cycles, persistent data storage and Application Architecture is a lot more important than the language you choose. Then learn and migrate to Kotlin. You can always convert your Java codes to Kotlin. If you can’t write something in kotlin, write it in java, convert and read.
But if you already know Java and Android, try Kotlin now!!!