I think picking a first language is relative to what you goal use is. You wouldn't learn R if you are looking to make video games. Java has a broad appeal to it and is applicable in a lot of places.
When I was in college in the early 2000's the language offering at my school was all C++ based. It was only in my last semester that they started to add Java courses. When I was looking for a job after graduating, everything was looking for Java and I had to learn it on the side to try to stay relevant. I didn't feel it was that difficult to apply what I already knew about C++ to Java
I think some languages like Java and C++ are similar and when you learn one you can kind of use that knowledge in the other. But some languages are a bit different and don't transfer over well (like Python). It is just like spoken languages where based on what you know, one language might be easier to learn than another because its structure is similar. As an English speaker, you will most likely have an easier time learning French or Spanish than Chinese or Japanese. Those languages are similar in structure and therefor you can apply what you already know to help you understand it faster than if you were learning something with a different structure.