It really depends what you want to build or what kind of job you want to have to be honest.
JavaScript is used very widely, and it's a worthwhile language to have under your belt because you can do pretty much anything with it these days, both front end and backend, and it also has a bunch of frameworks and libraries.
Python is often cited as a good entry point to programming because it is quite abstract and you can get things done pretty quickly using the read–eval–print loop. It's also favored in fields like data science.
But there are plenty of other languages to consider...
If you're interested in building apps, and you're passionate about Apple, then Objective C or Swift are wise options.
I'd recommend Swift if you want to build iOS apps for yourself, but Obj C is almost always a requirement if you're hoping to do it professionally. Luckily, acquiring one after the other isn't too much of a leap.
iOS developers seem to be super sought after too - so this could be a wise career choice.
