I'm doing Kotlin for Android. I started using Java, but switched once Kotlin became available here. I don't like Java as a language so was happy to switch. Kotlin has become my favorite language kicking C++ out after holding that spot for 33 years. The issue with doing Kotlin is you must still read some Java examples and convert them yourself to Kotlin. There are tons more this year over last and likely next year it will not be an issue any more. Personally, I suggest learning both and picking the one you like best.
I prefer java first...
if you learn java first, after you can divert to kotlin later. but kotlin first makes you miss java features.. it may become difficult to understand java if needed...
I am familiar with its syntax finished the course here and I was reading some documents, it is very similar to JS (syntax) I even kinda enjoyed strong typing like typescript :D , what do you think is the way to go starting from tomorrow ?